Patent Publication Number: US-2023137733-A1

Title: Microwave treatment apparatus and method for producing carbon fiber

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a U.S. National Phase Application under 35 U.S.C. § 371 of International Patent Application No. PCT/JP2018/046616, filed Dec. 18, 2018, which claims priority of Japanese Patent Application No. 2018-006744, filed Jan. 18, 2018 and Japanese Patent Application No. 2018-236423, filed Dec. 18, 2018. The entire contents of which are hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a microwave treatment apparatus and the like for performing treatment such as heating using microwaves. 
     BACKGROUND ART 
     As a conventional technique for performing treatment using microwaves, an apparatus is known including: a heating furnace body that is made of a microwave shielding material; a microwave part that introduces microwave power to the heating furnace body; a heating tubular member that is made of a heat conductive material having a microwave shielding function, and is provided along a straight line between an inlet port on one side of the heating furnace body and an outlet port on the other side thereof; a microwave heating element that is arranged around the outer circumference of the heating tubular member, and transfers heat to the heating tubular member; and filters that are arranged near the inlet port and the outlet port of the heating furnace body near the ends of the heating tubular member, and prevent leakage of microwave power, wherein a workpiece supplied from the inlet port is caused to pass through the heating tubular member and be discharged from the outlet port, and the workpiece is heated in the heating tubular member (see Japanese Patent No. 5877448, for example). 
     SUMMARY OF INVENTION 
     However, conventional techniques are problematic in that it is not possible to properly treat a treatment target using microwaves. 
     For example, according to conventional techniques, heating is performed with radiant heat of a microwave heating element heated using microwaves. Thus, a treatment target such as a workpiece can be heated only from the outside, and it is difficult to perform desired heating such as uniform heating. 
     Furthermore, a treatment target cannot be directly irradiated with microwaves, and thus the treatment target cannot be directly heated by microwaves. Thus, there is a problem in that the heating efficiency is poor. 
     The present invention was arrived at in order to solve the above-described problems, and it is an object thereof to provide a microwave treatment apparatus and the like capable of properly treating a treatment target using microwaves. 
     The present invention is directed to a microwave treatment apparatus including: a vessel in which a treatment target is arranged; a microwave irradiating unit that irradiates an internal portion of the vessel with microwaves; and a heat generating member that is provided inside the vessel along the treatment target, generates heat by absorbing part of microwaves used for irradiation by the microwave irradiating unit, and transmits part of the microwaves, wherein the microwave irradiating unit irradiates a portion in which the heat generating member is provided with microwaves, thereby heating the treatment target from an outside through heat generation of the heat generating member, and directly heating the treatment target with microwaves transmitted through the heat generating member. 
     With this configuration, it is possible to properly treat the treatment target, by combining heating from the heat generating member through microwave irradiation and direct heating of the treatment target. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that the treatment target moves inside the vessel, the heat generating member is provided along part of a movement path of the treatment target, and is not provided in other portions along the movement path, and the microwave irradiating unit performs first microwave irradiation by which the portion in which the heat generating member is provided on the movement path is irradiated with microwaves, thereby heating the heat generating member, and second microwave irradiation by which a portion in which the heat generating member is not provided on the movement path is irradiated with microwaves, thereby heating the treatment target. 
     With this configuration, it is possible to properly treat the treatment target, by combining heating of the treatment target from the heat generating member, and direct heating of the treatment target in the portion in which the heat generating member is not provided, on the movement path. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that the microwave irradiating unit includes: one or more first irradiating portions that perform the first microwave irradiation; and one or more second irradiating portions that perform the second microwave irradiation. 
     With this configuration, it is easy to individually control the power of the first microwave irradiation and the power of the second microwave irradiation, and thus it is possible to efficiently perform treatment on the treatment target, and to obtain a treatment result with a high quality. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that the microwave irradiating unit includes two or more irradiating portions that perform irradiation with microwaves from different positions, and phases of microwaves that are used for irradiation by the two or more irradiating portions are controlled, so that the first microwave irradiation in which microwaves used for irradiation by the two or more irradiating portions are intensified by each other at the heat generating member, and the second microwave irradiation in which microwaves used for irradiation by the two or more irradiating portions are intensified by each other at the treatment target are performed. 
     With this configuration, it is easy to set and change the position at which heating is performed through the first microwave irradiation and the position at which heating is performed through the second microwave irradiation, by controlling the phases. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that the microwave irradiating unit performs: first microwave irradiation by which the heat generating member is irradiated with microwaves with a frequency corresponding to a half-power depth at which microwaves absorbed by the heat generating member are greater than microwaves transmitted through the heat generating member; and second microwave irradiation by which the heat generating member is irradiated with microwaves with a frequency corresponding to a half-power depth at which microwaves absorbed by the heat generating member are less than microwaves transmitted through the heat generating member, so that the treatment target is irradiated with the microwaves transmitted through the heat generating member. 
     With this configuration, it is possible to properly heat the treatment target, by changing a combination of heating of the treatment target through heating of the heat generating member and direct heating of the treatment target, using microwaves with different frequencies. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that the microwave irradiating unit performs: first microwave irradiation by which the heat generating member is irradiated with microwaves with a frequency at which a relative dielectric loss in the heat generating member is larger than a relative dielectric loss in the treatment target; and second microwave irradiation by which the heat generating member is irradiated with microwaves with a frequency at which a relative dielectric loss in the heat generating member is smaller than a relative dielectric loss in the treatment target, so that the treatment target is irradiated with the microwaves transmitted through the heat generating member. 
     With this configuration, it is possible to properly heat the treatment target, by changing a combination of heating of the treatment target through heating of the heat generating member and direct heating of the treatment target, using microwaves with different frequencies. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that the treatment target moves inside the vessel, the heat generating member includes a first heat generating member that is provided along part of a movement path of the treatment target, and a second heat generating member that is provided along the movement path of the treatment target, at a portion in which the first heat generating member is not provided, wherein absorption of microwaves by the second heat generating member is less than that by the first heat generating member, and the microwave irradiating unit performs first microwave irradiation by which a portion in which the first heat generating member is provided is irradiated with microwaves, and second microwave irradiation by which a portion in which the second heat generating member is provided is irradiated with microwaves. 
     With this configuration, it is possible to change a combination of heating by the heat generating member and direct heating of the treatment target by microwaves transmitted through the heat generating member between the first heat generating member and the second heat generating member, and to properly treat the treatment target. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that the microwave irradiating unit includes an irradiating portion that irradiates an internal portion of the vessel with microwaves, the treatment target moves inside the vessel, the heat generating member is provided along a movement path of the treatment target so as to cover the treatment target, at part or the whole of the movement path, and a first microwave irradiation position at which microwaves used for irradiation by the irradiating portion are intensified in the heat generating member, and a second microwave irradiation position at which microwaves used for irradiation by the irradiating portion are intensified in the treatment target are provided along the movement path of the treatment target. 
     With this configuration, it is possible to properly treat the treatment target, by combining heating from the heat generating member at the first microwave irradiation position and direct heating of the treatment target at the second microwave irradiation position. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that multiple irradiating portions are provided along the movement path of the treatment target, and phases of microwaves that are used for irradiation by the irradiating portions are controlled, so that intensity of microwaves at the irradiation positions is controlled. 
     With this configuration, it is easy to set and change the irradiation positions, by controlling the phases. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that multiple irradiating portions are provided along the movement path of the treatment target, and frequencies of microwaves that are used for irradiation by the irradiating portions are controlled according to properties (material/thickness) of the treatment target and/or the heat generating member, so that absorptions of microwaves at the irradiation positions are controlled. 
     With this configuration, it is possible to properly heat the treatment target, by changing a combination of heating of the treatment target through heating of the heat generating member and direct heating of the treatment target, by controlling the frequencies. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may further include: a first sensor that acquires information of temperature of the heat generating member at the first microwave irradiation position; a second sensor that acquires information of temperature of the treatment target at the second microwave irradiation position; and a control unit that performs feedback control on power of microwaves for use in the microwave irradiation, using the information of temperature acquired by the first sensor. 
     With this configuration, it is possible properly control the heating at the first microwave irradiation position and the heating at the second microwave irradiation position. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that the heat generating member is provided along part of a movement path of the treatment target, and is not provided in other portions along the movement path, the second microwave irradiation position is a position at which microwaves used for irradiation by the irradiating portion are intensified in the treatment target in a portion in which the heat generating member is not provided, and the microwave treatment apparatus is further provided with a third microwave irradiation position at which microwaves used for irradiation by the irradiating portion are intensified in the treatment target in a portion in which the heat generating member is provided. 
     With this configuration, it is possible to properly treat the treatment target, by combining heating from the heat generating member at the first microwave irradiation position, direct heating of the treatment target at the second microwave irradiation position, and direct heating of the treatment target at the third microwave irradiation position in a portion in which the heat generating member having the first microwave irradiation position is provided. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that one or more first microwave irradiation positions and one or more third microwave irradiation positions are the same position in a direction that is along the movement path. 
     With this configuration, it is possible to properly treat the treatment target, by combining heating from the heat generating member at the first microwave irradiation position and direct heating of the treatment target at the third microwave irradiation position, at the same position in the direction that is along the movement path. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that two or more heat generating members are provided along the movement path such that an area in which no heat generating member is provided is interposed therebetween, and one or more first microwave irradiation positions and one or more third microwave irradiation positions are provided in portions in which different heat generating members are provided. 
     With this configuration, it is possible to individually perform heating from the heat generating member at the first microwave irradiation position and direct heating of the treatment target at the third microwave irradiation position, on the treatment target in portions in which different heat generating members are provided, and to properly treat the treatment target. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that phases of microwaves that are used for irradiation by the irradiating portion are controlled such that microwaves are intensified at the first microwave irradiation position and the second microwave irradiation position. 
     With this configuration, it is easy to set and change the first microwave irradiation position and the second microwave irradiation position. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that the microwave irradiating unit performs the second microwave irradiation using microwaves with a frequency that is different from that in the first microwave irradiation. 
     With this configuration, it is possible to properly control the heating through the first microwave irradiation and the heating through the second microwave irradiation, using different frequencies. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that the frequency of microwaves for use in the first microwave irradiation is a frequency at which a relative dielectric loss in the heat generating member is larger than a relative dielectric loss in the treatment target. 
     With this configuration, it is possible to efficiently heat the heat generating member in the first microwave irradiation. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that the microwave irradiating unit further performs third microwave irradiation by which a portion in which the heat generating member is provided is irradiated with microwaves with a frequency at which a relative dielectric loss in the heat generating member is smaller than a relative dielectric loss in the treatment target, thereby heating the treatment target in the portion in which the heat generating member is provided. 
     With this configuration, it is possible to efficiently heat the treatment target in a portion in which the heat generating member is provided, in the third microwave irradiation. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that one or more positions irradiated with microwaves by the first microwave irradiation and one or more positions irradiated with microwaves by the third microwave irradiation are the same position in a direction that is along the movement path. 
     With this configuration, it is possible to properly treat the treatment target in the portion in which the heat generating member is provided, through heating from the heat generating member in the first microwave irradiation and direct heating of the treatment target in the third microwave irradiation, at the same position in the direction that is along the movement path. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that two or more heat generating members are provided along the movement path such that an area in which no heat generating member is provided is interposed therebetween, and one or more positions irradiated with microwaves by the first microwave irradiation and one or more positions irradiated with microwaves by the third microwave irradiation are provided in portions in which different heat generating members are provided. 
     With this configuration, it is possible to individually perform heating from the heat generating member through the first microwave irradiation and direct heating of the treatment target through the third microwave irradiation, on the treatment target in portions in which different heat generating members are provided, and to properly treat the treatment target. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that the heat generating member has a tubular shape, and the microwave treatment apparatus further includes a gas supply unit that supplies predetermined gas into the heat generating member. 
     With this configuration, it is possible to properly treat the treatment target, by supplying gas into the heat generating member. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that the treatment target moves inside the vessel, and at least a portion on a treatment target side in the heat generating member includes a non-transmitting portion that does not transmit microwaves. 
     With this configuration, it is possible to provide a portion that prevents the treatment target from being directly irradiated with microwaves, and thus it is possible to increase the width of the microwave irradiation control. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that the heat generating member is a member that assists conveyance of the treatment target inside the vessel, and includes a heating medium that generates heat by absorbing microwaves at a portion that comes into contact with the treatment target. 
     With this configuration, it is possible to perform heating from the heat generating member, through heat conduction from the heating medium that is in contact with the treatment target, and thus it is possible to improve the thermal efficiency. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may be such that the treatment target is a precursor fiber of a carbon fiber, and the microwave treatment apparatus is for use in flame-resistance treatment on the precursor fiber. 
     With this configuration, it is possible to obtain a precursor of a carbon fiber with a high quality, which has undergone flame-resistance treatment. 
     Furthermore, according to the microwave treatment apparatus of the present invention, the microwave treatment apparatus may further include: a first sensor that acquires information of temperature of the heat generating member at a portion in which the first microwave irradiation is performed; a second sensor that acquires information of temperature of the treatment target at a portion in which the second microwave irradiation is performed; and a control unit that performs feedback control on power of microwaves for use in the first microwave irradiation, using the information of temperature acquired by the first sensor, and performs feedback control on power of microwaves for use in the second microwave irradiation, using the information of temperature acquired by the second sensor. 
     With this configuration, it is possible to properly control the heating of the heat generating member through the first microwave irradiation and the heating of the treatment target through the second microwave irradiation. 
     The present invention is further directed to a method for producing a carbon fiber, including a step of irradiating an internal portion of a vessel with microwaves, the vessel including, therein, a heat generating member that generates heat by absorbing part of microwaves used for irradiation, and transmits part of the microwaves, thereby heating a precursor fiber of a carbon fiber that is provided along the heat generating member, wherein, in the heating step, a portion in which the heat generating member is provided is irradiated with microwaves, so that the precursor fiber is heated from an outside through heat generation of the heat generating member, and the precursor fiber is directly heated with microwaves transmitted through the heat generating member. 
     With this configuration, it is possible to properly treat the treatment target, by combining heating from the heat generating member through microwave irradiation and direct heating of the treatment target. 
     According to the present invention, it is possible to properly treat a treatment target using microwaves. 
    
    
     
       BRIEF DESCIPTION OF DRAWINGS 
         FIG.  1    is a cross-sectional view of a microwave treatment apparatus in Embodiment 1 of the present invention. 
         FIG.  2    shows a view showing a heat generating member of the microwave treatment apparatus in the embodiment ( FIG.  2 A ), and views showing modified examples thereof ( FIGS.  2 B to  2 D ). 
         FIG.  3    is a cross-sectional view showing a modified example of the microwave treatment apparatus in the embodiment. 
         FIG.  4    shows cross-sectional views showing a modified example of the microwave treatment apparatus in the embodiment ( FIGS.  4 A and  4 B ). 
         FIG.  5    shows a cross-sectional view of the microwave treatment apparatus in Embodiment 2 of the present invention ( FIG.  5 A ), and schematic cross-sectional views thereof ( FIGS.  5 B and  5 C ). 
         FIG.  6    is a cross-sectional view of the microwave treatment apparatus in Embodiment 3 of the present invention ( FIG.  6 A ), and schematic cross-sectional views thereof ( FIGS.  6 B to  6 D ). 
         FIG.  7    is a schematic cross-sectional view illustrating a modified example of the microwave treatment apparatus in Embodiment 2 of the present invention ( FIG.  7 A ), and schematic views thereof ( FIGS.  7 B to  7 D ). 
         FIG.  8    shows schematic views illustrating a modified example of the microwave treatment apparatus in Embodiment 3 ( FIGS.  8 A to  8 D ). 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     Hereinafter, embodiments of a microwave treatment apparatus and the like will be described with reference to the drawings. It should be noted that constituent elements denoted by the same reference numerals in the embodiments perform similar operations, and thus a description thereof may not be repeated. 
     Embodiment 1 
     Hereinafter, a microwave treatment apparatus will be described using, as an example, an apparatus that performs flame-resistance treatment on a precursor fiber that is used to produce a carbon fiber. 
     First, an example of the production process of a carbon fiber will be described. A precursor fiber made of polyacrylonitrile (PAN) or the like is heated in heated air at 200 to 300° C. for 60 to 120 minutes, so that oxidation of the precursor fiber is performed. This treatment is referred to as flame-resistance treatment. In this treatment, a cyclization reaction of a precursor fiber is caused to occur, so that a flame-resistant fiber is obtained through oxygen binding. 
     Subsequently, the obtained flame-resistant fiber is heated in a nitrogen atmosphere at 1000 to 1500° C. for several minutes, so that the fiber carbonized, and a carbon fiber can be obtained. 
       FIG.  1    is a cross-sectional view that is parallel to the movement direction of a treatment target, illustrating a microwave treatment apparatus in this embodiment. 
     A microwave treatment apparatus  1  includes a vessel  10 , a microwave irradiating unit  20 , heat generating members  30 , one or at least two sensors  40 , a control unit  50 , and a conveying unit  60 . 
     The vessel  10  is made of a microwave-reflecting material such as stainless steel. The vessel  10  is in the shape of a box that is hollow and horizontally long. The treatment target  2  is arranged inside the vessel  10 . In this case, for example, it is assumed that the treatment target  2  is a PAN-based precursor fiber. A precursor fiber that is the treatment target  2  may be, for example, one precursor fiber, or multiple precursor fibers bundled into a string or cord shape. There may be either one or multiple treatment targets  2  that are arranged inside the vessel  10 . In the description below, an example in which the treatment target  2  that is arranged inside the vessel  10  moves inside the vessel  10  will be described. This movement may be continuous movement, or non-continuous movement in which movement and stoppage is combined. For example, it is also possible that movement of the treatment target  2  is stopped when microwave irradiation is performed in the vessel  10 , and the treatment target  2  is moved when microwave irradiation is not performed. This movement may be movement whose movement speed is constant, or movement whose movement speed continuously or non-continuously changes. The same applies to other embodiments. In the description below, as an example, a case will be described in which the treatment target  2  continuously moves. 
     One of the two ends in the longitudinal direction of the vessel  10  is provided with an inlet  101   a  of the treatment target  2 , and the other is provided with an outlet  101   b . The treatment target  2  enters the vessel  10  from the inlet  101   a , moves inside the vessel  10 , and exits the vessel  10  to the outside from the outlet  101   b . Hereinafter, a case will be described as an example in which the treatment target  2  substantially horizontally moves inside the vessel  10 . Note that there is no limitation on the movement direction or the movement paths of treatment targets inside and outside the vessel  10 . For example, it is also possible that the movement direction of treatment targets is changed at a point on the path by a roller or the like, or that, for example, the movement direction of precursor fibers is turned once or more by a roller or the like. Typically, the vessel  10  is arranged such that its longitudinal direction is horizontal, but the vessel  10  may be inclined. The inlet  101   a  and the outlet  101   b  are provided with filters (not shown) for preventing microwaves with which the internal portion of the vessel  10  is irradiated from leaking to the outside. Examples of the filters include those having a choke structure or the like using the wavelength properties of microwaves, and configured to prevent microwave power from passing therethrough in a non-contact manner. The inlet  101   a  and the outlet  101   b  may have a structure for preventing leakage of microwaves, other than filters. There is no limitation on the size of the vessel  10  and the thickness of the outer wall of the vessel  10  and the like. It is also possible that the outer wall of the vessel  10  is provided with a heat insulating material (not shown) or the like. The size of the vessel  10  and the like are determined, for example, according to the treatment target, the treatment time, and the like. 
     The above-described shape of the vessel  10  is merely an example, and the vessel  10  may have any shape other than that described above. For example, it is also possible that the shape of the vessel  10  is a cylindrical shape that is elongated in the horizontal direction, a polygonal prism shape, or a shape obtained by combining these shapes. It is also possible that the vessel  10  is in a shape that is elongated in the vertical direction. It is also possible that movement path  2   a  of the treatment target  2  is folded with unshown rollers or the like such that the movement direction of the treatment target  2  is alternately reversed in the horizontal direction, and the vessel  10  is shaped such that at least the portion of the movement path  2   a  in which the treatment target  2  moves in parallel is covered. In this example, for the sake of ease of description, the treatment target  2  is shown so as to overlap the movement path  2   a . On the movement path  2   a , the movement direction of the treatment target  2  is indicated by the orientation of the arrows. The same applies to the description below. 
     The shape, the size, and the like of the vessel  10  are determined, for example, according to the distribution of microwaves with which the internal portion of the vessel  10  is irradiated. For example, the shape and the size of the vessel  10  are preferably set such that the mode of microwaves in the vessel  10  is a multi-mode. The multi-mode of microwaves is, for example, a mode in which there is no stationary waves of microwaves inside the vessel  10 . 
     There is no limitation on the positions at which the inlet  101   a  and the outlet  101   b  are provided in the vessel  10 . For example, it is also possible that the inlet  101   a  and the outlet  101   b  are provided at the same end, side faces, or the like of the vessel  10 . The vessel  10  may have multiple inlets  101   a  and outlets  101   b , and, for example, the movement direction of the treatment target  2  may be changed by unshown rollers or the like so that the treatment target  2  enters the vessel  10  via the multiple inlets  101   a  and exits the vessel  10  via the multiple outlets  101   b.    
     It is preferable that the vessel  10  has a structure that is closed so as to prevent microwaves from leaking, at portions other than those that need to be open, such as the inlet  101   a  and the outlet  101   b  of the treatment target  2 , later-described opening portions  102 , and the like. 
     Although not shown, the outer periphery of the vessel  10  may be provided with a hot water jacket, a cold water jacket, a heater, or the like for adjusting the temperature of the vessel  1 . Also, the vessel  10  may be provided with an unshown observation window through which the internal portion of the vessel  10  can be observed, a ventilating hole and a fan for supplying and exhausting air, and the like. 
       FIG.  2    shows a perspective view schematically showing the heat generating member  30  of the microwave treatment apparatus  1  of this embodiment ( FIG.  2 A ), perspective views schematically showing modified examples of the heat generating member  30  ( FIGS.  2 B and  2 C ), and a cross-sectional view taken along the movement path  2   a  of the treatment target  2 , illustrating the modified example of the heat generating member  30  shown in  FIG.  2 A  ( FIG.  2 D ). In the vessel  10 , the heat generating members  30  that generate heat by absorbing microwaves used for irradiation by the microwave irradiating unit  20  are provided. It is preferable that, for example, the heat generating members  30  generate heat by absorbing part of microwaves used for irradiation by the microwave irradiating unit  20 , and transmit part of the microwaves. The heat generating members  30  are provided along the treatment target  2  that is arranged inside the vessel  10 . The state of being provided along the treatment target  2  may be considered, for example, as a state of being provided along the outer periphery of the treatment target  2 , or a state of being provided around the treatment target  2 . The gap between the heat generating members  30  and the treatment target  2  may be constant or may vary in the longitudinal direction or the movement direction of the treatment target  2 , and, in either case, the heat generating members  30  may be considered as being provided along the treatment target. Also, the gap between the portions of each heat generating member  30  that face each other with the treatment target  2  interposed therebetween may be constant or may vary, and, in either case, the heat generating members  30  may be considered as being provided along the treatment target. In this example, the treatment target  2  moves inside the vessel  10 , and thus the heat generating members  30  are provided along the movement path  2   a  of the treatment target  2 . For example, the shape of each heat generating member  30  may be any shape, as long as it covers the treatment target  2 . The shape of the heat generating member  30  is preferably a cylindrical shape that surrounds the outer periphery of the treatment target  2  as shown in  FIG.  2 A , but, for example, the shape may be a tubular shape other than a cylindrical shape, such as a ring-like shape or a shape whose cross-section that is perpendicular to the movement direction of the treatment target  2  is in the shape of the letter “U” as shown in  FIG.  2 C . It is also possible that the heat generating member  30  is constituted by two plate-like members that are arranged such that the treatment target  2  is interposed therebetween as shown in  FIG.  2 B . Furthermore, the heat generating member  30  may have a tubular shape that partially bulges, a tubular shape that is partially recessed, a tubular shape that is partially curved, or the like. 
     As shown in  FIGS.  2 A to  2 C , the heat generating member  30  includes a heating medium  301  that generates heat by absorbing microwaves used for irradiation, and a support member  302  that supports the heating medium  301 . Typically, the heating medium  301  is arranged on the side face of the support member  302  that does not face the treatment target  2 . This side face is, for example, a face that is parallel to the movement direction of the treatment target  2 . The heating medium  301  is made of, for example, a heating element such as carbon, SiC, a carbon fiber composite material, a metal silicide (e.g., molybdenum silicide or tungsten silicide), or a ceramic material containing a powder or the like of these heating elements, or the like. The heating medium  301  has, for example, a material and a thickness that allow the heating medium  301  to generate heat by absorbing part of microwaves with which the heat generating member  30  is irradiated, and transmit part of the microwaves used for irradiation. The heating medium  301  has, for example, a material and a thickness that allow the heating medium  301  to transmit part of microwaves with which the heat generating member  30  is irradiated. The heating medium may be a metal layer with a thickness that allows the heating medium to partially transmit microwaves, such as a metal layer with a thickness of several micrometers. The support member  302  is made of a material with high microwave transmission, such as ceramics or glass. The heating medium  301  is formed by, for example, applying or attaching the material of the heating medium  301  to the surface of the support member  302 . If the heating medium  301  alone has sufficient strength as in the case in which the heating medium  301  is made of ceramics containing heating elements, the support member  302  may be omitted. The heating medium  301  has, for example, a material and a thickness that allow the heating medium  301  to transmit part of microwaves with which the heat generating member  30  is irradiated. If the support member  302  is used to reinforce the heating medium  301  or to keep the shape of the heating medium  301 , the heat generating member  30  may be considered as being constituted only by the heating medium  301 . The heat generating member  30  is preferably such that, for example, heat generation by irradiation of the heat generating member  30  with microwaves is greater than heat generation at the treatment target  2  by microwaves transmitted through the heat generating member  30 , and the heat generating member  30  preferably has a material and a thickness with which, for example, heat generation by irradiation of the heat generating member  30  with microwaves is greater than heat generation at the treatment target  2  by microwaves transmitted through the heat generating member  30 . In this case, the material and the thickness of the heat generating member  30  may be considered as the material and the thickness of the heating medium  301 . For example, assuming that a treatment target  2  is one precursor fiber, the heat generating member  30  in the shape of a cylinder has an inner diameter of approximately 9 to 12 mm, or 11 to 14 mm, and the heat generating member  30  has a thickness of approximately 2 to 5 mm. Note that they may have sizes other than these mentioned above. 
     For example, the heat generating members  30  may be provided at part of the internal portion of the vessel  10  in the longitudinal direction or the movement direction of the treatment target  2 , or may be provided throughout the internal portion of the vessel  10  in the longitudinal direction or the movement direction of the treatment target  2 . For example, the multiple heat generating members  30  may be provided along the longitudinal direction or the movement direction of the treatment target  2  at desired intervals. In this example, a case will be described in which the heat generating members  30  in the shape of cylinders as shown in  FIG.  2 A  are provided along part of the movement path  2   a  of the treatment target  2 . Specifically, as shown in  FIG.  1   , three heat generating members  30  in the shape of cylinders are provided at intervals such that the treatment target  2  moves inside the heat generating members  30 . In this example, the three heat generating members  30  are denoted by heat generating members  30   a  to  30   c  sequentially from the inlet  101   a  side of the vessel  10 . Note that, if they do not have to be distinguished from each other, they are collectively referred to as heat generating members  30 . The same applies to other irradiating portions  201 , irradiating portions  202 , sensors  40 , and the like. The lengths in the movement direction of the treatment target  2  of the heat generating members  30  (hereinafter, referred to as lengths of the heat generating members  30 ), that is, the lengths in the longitudinal direction of the cylindrical shapes may be the same or different from each other, and there is no limitation on the lengths. For example, if the treatment target  2  moves inside the vessel  10 , the lengths of the heat generating members  30  may be considered as corresponding to the heating time using the heat generating members  30 . The intervals between the heat generating members  30  may or may not be equal intervals, and there is no limitation on the distances thereof. For example, if the treatment target  2  moves inside the vessel  10 , the intervals between the heat generating members  30  in the movement direction, the distance between heat generating member  30  that is the closest to the inlet  101   a  and the inlet  101   a , and the distance between the heat generating member  30  that is the closest to the outlet  101   b  and the outlet  101   b  (hereinafter, referred to as the length of a portion in which the heat generating member is not provided) may be considered as corresponding to the heating time not using the heat generating members  30 . The distance between the heat generating members  30  and the inlet  101   a  of the vessel  10 , and the distance between the heat generating members  30  and the outlet  101   b  of the vessel  10  may or may not be equal distances, and there is no limitation on the distances thereof. In this example, there is no limitation on the diameters and the like of the heat generating members  30  in the shape of cylinders. The diameters of the heat generating members  30  may be the same or different from each other. In this example, the heat generating members  30  are not in contact with the treatment target  2 , but it is also possible that the heat generating members  30  are at least partially in contact with the treatment target. The heat generating members  30  are provided such that their side faces are not in contact with the vessel  10 . 
     In this example, for the sake of ease of description, the case was described in which three heat generating members  30  are provided, but it is sufficient that the number of heat generating members  30  is one or more. For example, if the microwave treatment apparatus  1  is for use in flame-resistance treatment on precursor fibers of carbon fibers that move inside the vessel  10 , it is sufficient to set the number of heat generating members to the necessary number of times of heating using the heat generating members  30 . In this case, for example, it is sufficient to set the length of each heat generating member  30  to the length corresponding to the period of time necessary for the heating using the heat generating member  30 , and to set the length of the portion in which the heat generating member  30  is not provided to the period of time necessary for the heating not using the heat generating member  30 . For example, if the movement path  2   a  of the treatment target  2  is bent, for example, one or more heat generating members  30  may be provided in both of the portion before the bending and the portion after the bending, and, in this case, the heat generating members  30  do not have to be provided on the same straight line. 
     The microwave irradiating unit  20  irradiates the internal portion of the vessel  10  with microwaves. For example, the microwave irradiating unit  20  is attached to the vessel  10 . The microwave irradiating unit  20  performs first microwave irradiation by which the heat generating members  30  are heated, and second microwave irradiation by which the treatment target  2  is heated. The heating the heat generating members  30  may be, for example, heating only the heat generating members  30 , or heating the heat generating members  30  at intensity that is higher than that at the treatment target  2 . The heating the treatment target  2  may be, for example, heating only the treatment target  2 , or heating the treatment target  2  at intensity that is higher than that at the heat generating members  30 . Note that the first microwave irradiation is preferably heating that heats the treatment target  2  as well. 
     The first microwave irradiation is, for example, microwave irradiation in which heat generation at the heat generating members  30  through microwave irradiation is greater than heat generation at the treatment target  2 . The first microwave irradiation may be considered as microwave irradiation in which heat generation at the heat generating members  30  is dominant. For example, this heat generation may be considered as the amount of heat generated. This heat generation at the heat generating members  30  may be considered as the amount of heat generated by microwaves and received by the treatment target  2  from the heat generating members  30 . 
     The second microwave irradiation is, for example, microwave irradiation in which heat generation at the treatment target  2  through microwave irradiation is greater than heat generation at the heat generating members  30 . The second microwave irradiation may be considered as microwave irradiation in which heat generation at the treatment target  2  is dominant. This heat generation may be considered as the amount of heat generated by microwaves and directly received by or applied to the treatment target  2 . 
     In this embodiment, a case will be described in which the microwave irradiating unit  20  includes one or at least two first irradiating portions  201  that perform first microwave irradiation, and one or at least two second irradiating portions  202  that perform second microwave irradiation. 
     The first irradiating portions  201  performs first microwave irradiation by which the portions in which the heat generating members  30  are provided on the movement path  2   a  of the treatment target  2  are irradiated with microwaves, thereby heating the heat generating members  30 . That is to say, the first microwave irradiation that is performed by the first irradiating portions  201  is microwave irradiation to the portions in which the heat generating members  30  are provided on the movement path  2   a  of the treatment target  2 . In the first microwave irradiation, heat is preferably generated at the treatment target  2  as well. For example, the first microwave irradiation that is performed by the first irradiating portions  201  is microwave irradiation in which heat generation at the heat generating members  30  due to absorption of part of microwaves that used for irradiation and heat generation at the treatment target  2  due to absorption of part of microwaves that are transmitted through the heat generating members  30  occur, and is microwave irradiation in which heat generation at the heat generating members  30  is greater than heat generation at the treatment target  2 . 
     The first microwave irradiation is microwave irradiation to the heat generating members  30 , in which heating of the treatment target  2  from the outside through heat generation at the heat generating members  30  is greater than direct heating of the treatment target due to microwaves transmitted through the heat generating members  30 . For example, it is preferable that the material, the thickness, and the like of the heat generating members  30  are set such that the treatment target  2  and the like are heated as described above by microwaves absorbed by the heat generating members  30  and microwaves transmitted through the heat generating members  30 . 
     Furthermore, the second irradiating portions  202  perform second microwave irradiation by which the portions in which the heat generating members  30  are not provided on the movement path  2   a  of the treatment target  2  are irradiated with microwaves, thereby heating the treatment target  2 . That is to say, the second microwave irradiation that is performed by the second irradiating portions  202  is microwave irradiation to the portions in which the heat generating members  30  are not provided on the movement path  2   a  of the treatment target  2 . In the second microwave irradiation that is performed by the second irradiating portions  202 , the heat generating members  30  are not provided at the positions that are irradiated with microwaves, and thus the treatment target  2  is not heated from the outside by heat generation at the heat generating members  30  and the like. Accordingly, direct heating of the treatment target  2  through microwave irradiation is greater than heating of the treatment target  2  from the outside by the heat generating members  30  and the like that are irradiated with microwaves. 
     Hereinafter, in this embodiment, as an example, a case will be described in which the microwave treatment apparatus  1  includes three first irradiating portions  201  and three second irradiating portions  202  as shown in  FIG.  1   , but there is no limitation on the numbers thereof. In this example, for the sake of ease of description, the three first irradiating portions  201  are denoted by first irradiating portions  201   a  to  201   c  sequentially from the inlet  101   a  side of the vessel  10 , and the three second irradiating portions  202  are denoted by second irradiating portions  202   a  to  202   c  sequentially from the inlet  101   a  side of the vessel  10 . It is preferable that the power (e.g., wattage, etc.) of microwaves from the one or at least two first irradiating portions  201  and the one or at least two second irradiating portions  202  included in the microwave irradiating unit  20  can be individually changed. For example, the power of the first irradiating portions  201  and the second irradiating portions  202  is controlled according to control signals and the like from a later-described control unit  50 . In the microwave treatment apparatus  1  in which multiple heat generating members  30  are provided as shown in  FIG.  1   , it is preferable that one or more first irradiating portions  201  are provided at positions from which the heat generating members  30  can be directly irradiated with microwaves, and that one or more second irradiating portions  202  are provided, for example, at positions from which at least one or more of the areas between the heat generating members  30 , the area between the heat generating member  30  that is the closest to the inlet  101   a  and the inlet  101   a , and the area between the heat generating member  30  that is the closest to the outlet  101   b  and the outlet  101   b  can be directly irradiated with microwaves. 
     Each of the first irradiating portions  201  and the second irradiating portions  202  includes, for example, a microwave oscillator  2001 , and a transmitting portion  2002  that transmits microwaves generated by the microwave oscillator  2001 , into the vessel  10 . The microwave oscillators  2001  may be any type of microwave oscillators  2001 , and examples thereof include magnetrons, klystrons, gyrotrons, semiconductor oscillators, and the like. There is no limitation on the frequency, the intensity, and the like of microwaves that are emitted by the microwave oscillators  2001 . The frequency of microwaves that are emitted by the microwave oscillators  2001  may be, for example, 915 MHz, 2.45 GHz, 5.8 GHz, or other frequencies ranging from 300 MHz to 300 GHz, and there is no limitation on the frequency thereof. Examples of the transmitting portions  2002  include waveguides, coaxial cables for transmitting microwaves, and the like. 
     For example, the first irradiating portions  201  and the second irradiating portions  202  are attached to the vessel  10 , and irradiate the internal portion of the vessel  10  with microwaves. For example, the first irradiating portions  201  and the second irradiating portions  202  are such that ends of the transmitting portions  2002  to which the microwave oscillators  2001  are not attached are attached to opening portions  102  formed through the wall face of the vessel  10  or the like, and the internal portion of the vessel  10  is irradiated with microwaves emitted by the microwave oscillators  2001  and transmitted through the transmitting portions  2002  through the opening portions  102 . The ends of the transmitting portions  2002  attached to the opening portions  102  may be further provided with antennas (not shown) and the like for emitting microwaves transmitted through the transmitting portions  2002 . The opening portions  102  may be covered by a material with high microwave transmission such as a fluorinated polymer (e.g., polytetrafluoroethylene: PTFE), glass, rubber, nylon, or the like. The first irradiating portions  201  and the second irradiating portions  202  may be portions other than those described above, as long as the internal portion of the vessel  10  can be irradiated with microwaves. 
     The first irradiating portions  201  are attached to the vessel  10  such that the portions in which the heat generating members  30  are provided on the movement path  2   a  of the treatment target  2  in the vessel  10  are irradiated with microwaves. These portions may be considered as areas. For example, the ends of the transmitting portions  2002  of the first irradiating portions  201  are respectively attached to the opening portions  102  formed on the wall face of the vessel  10 , at positions that face the portions in which the heat generating members  30  are provided on the movement path  2   a . In this example, a case is shown in which one first irradiating portion  201  is provided at one opening portion  102  that is formed at the portion in which one heat generating member  30  is provided, but it is also possible that multiple first irradiating portions  201  are respectively attached to multiple opening portions  102  that are formed at the portion in which one heat generating member  30  is provided. 
     The second irradiating portions  202  are attached to the vessel  10  such that the portions in which the heat generating members  30  are not provided on the movement path  2   a  of the treatment target  2  in the vessel  10  are irradiated with microwaves. Specifically, the multiple second irradiating portions  202  are attached such that each of the portions between the heat generating members  30 , and the portion between the heat generating member  30  that is on the most downstream side on the movement path  2   a  and the outlet  101   b  of the vessel  10  is irradiated with microwaves. For example, the ends of the transmitting portions  2002  of the second irradiating portions  202  are respectively attached to the opening portions  102  formed on the wall face of the vessel  10 , at positions that face the portions in which the portions in which the heat generating members  30  are not provided on the movement path  2   a . In this example, a case is shown in which one first irradiating portion  201  is provided at one opening portion  102  that is formed at one portion in which no heat generating member  30  is provided, but it is also possible that multiple first irradiating portions  201  are respectively attached to multiple opening portions  102  that are formed at one portion in which no heat generating member  30  is provided. 
     In this example, it is assumed that microwaves that are used for irradiation by the first irradiating portions  201  and the second irradiating portions  202  are microwaves with the same frequency. Note that it is also possible that one or more of the multiple first irradiating portions  201  and multiple second irradiating portions  202  performs irradiation with microwaves with a frequency that is different from those of the other irradiating portions. 
     One or more sensors  40  for acquiring information such as the status of treatment target and the status inside the vessel are provided inside the vessel  10 . The sensors  40  may be sensors for acquiring any type of status information. For example, they may be temperature sensors for acquiring information of the temperature inside the vessel, humidity sensors s for acquiring information of the humidity inside the vessel, or the like. Alternatively, they may be sensors for detecting discharge inside the vessel due to microwaves, or the like. 
     In this example, a case will be described as an example in which the sensors  40  are radiation thermometers, and six sensors  40  are provided inside the vessel  10 . In this example, for the sake of ease of description, the six sensors  40  are denoted by sensors  40   a  to  40   f  sequentially from the inlet  101   a  side of the vessel  10 . A radiation thermometer is a thermometer for measuring the temperature of an object by measuring the intensity of infrared rays or visible rays emitted from the object. In this example, the sensors  40   a  to  40   c  that are radiation thermometers are provided near the outlet  101   b  sides in the areas in which the heat generating members  30  are provided on the movement path  2   a , in order to measure the temperature of the treatment target  2  immediately before exiting the areas in which the heat generating members  30  are provided. 
     Specifically, the sensors  40   a  to  40   c  are attached to the vessel  10  such that their positions in the horizontal direction are respectively near the outlet  101   b  sides in the heat generating members  30   a  to  30   c . Although not shown, it is assumed that, as an example, opening portions such as slits that are elongated in the horizontal direction for detecting the temperature of the treatment target  2  is formed through the heat generating members  30   a  to  30   c , at the portions thereof between the sensors  40   a  to  40   c  and the treatment target  2 . The sensors  40   d  to  40   f  that are the other radiation thermometers are provided near the outlet  101   b  sides in the areas in which the heat generating members  30  are not provided on the movement path  2   a , in order to measure the temperature of the treatment target  2  immediately before exiting the areas in which the heat generating members  30  are not provided. Specifically, the sensors  40   d  and  40   e  are attached to the vessel  10  such that their positions in the horizontal direction are respectively on the upstream sides in the heat generating members  30   b  and  30   c  in the movement direction of the treatment target  2 , and the sensor  40   f  is attached to the vessel  10  such that its position in the horizontal direction is on the upstream side of the outlet  101   b . For example, the sensors  40  acquire information of temperature, by measuring the intensity of infrared rays or the like emitted from the treatment target  2  in the direction that is orthogonal to the movement path  2   a . Note that the positions to which the sensors  40  are attached may be other positions. The sensors  40  are attached to, for example, opening portions or the like formed through the wall face of the vessel  10 . A precursor fiber is, for example, one fiber with a thickness of approximately 1 mm obtained by twisting several thousands of fibers, and thus, if the treatment target  2  is a precursor fiber, its surface temperature may be regarded as being the same as the temperature inside the precursor fiber. 
     The control unit  50  controls microwaves that are used for irradiation by the microwave irradiating unit  20 . For example, the control unit  50  controls the power of microwaves that are used for irradiation by the microwave irradiating unit  20 . For example, the control unit  50  controls the power of microwaves that are used for irradiation by the microwave irradiating unit  20 , according to the information acquired by the sensors  40 . 
     In this example, specifically, the control unit  50  performs feedback control on the power of microwaves that are used for irradiation by the first irradiating portions  201  that are configured to irradiate the areas in which the heat generating members  30  are provided on the movement path  2   a  with microwaves, using the information of temperature acquired by the sensors  40  that are provided on the outlet  101   b  sides in the areas in which the heat generating members  30  are provided. The control unit  50  performs feedback control on the power of microwaves that are used for irradiation by the second irradiating portions  202  that are configured to irradiate the areas in which the heat generating members  30  are not provided on the movement path  2   a  with microwaves, using the information of temperature acquired by the sensors  40  that are provided on the outlet  101   b  sides in the areas in which the heat generating members  30  are not provided. The areas in which the heat generating members  30  are provided and the areas in which the heat generating members  30  are not provided in this case are, for example, areas that are defined by virtual faces that are perpendicular to the movement path  2   a . For example, if the temperature acquired by the sensor  40   a  is higher than a first threshold value, the control unit  50  decreases the power of microwaves that are used for irradiation by the corresponding second irradiating portion  202   a , and, if the temperature is lower than a second threshold value, the control unit  50  increases the power of microwaves that are used for irradiation. It is assumed that the first threshold value in this case is a value that is higher than the second threshold value. 
     The control that is performed by the control unit  50  may be control other than the feedback control. There is no limitation on which irradiating portion is subjected to the control of power by the control unit  50  according to the information acquired by which sensor  40 . For example, it is also possible that the control unit  50  controls the power of one or more irradiating portions, according to the output of multiple sensors  40 . Also, it is also possible that the control unit  50  controls the power of multiple irradiating portions, according to the output of one sensor  40 . 
     Furthermore, it is also possible that one or more sensors  40  acquire information indicating the status of the heat generating members  30  such as the temperature of one or more heat generating members  30 , one heat generating member  30  at different positions, or the like, and the control unit  50  performs control (e.g., feedback control, etc.) on the power of one or more irradiating portions, using the information indicating that status. For example, it is also possible that information of the temperatures of the heat generating members  30  acquired by the sensors  40  configured to acquire information of the temperatures of the heat generating members  30  may be used to perform feedback control on the power of microwaves for use in the first microwave irradiation that is performed to each of the heat generating members  30 . 
     Furthermore, it is also possible that some of the sensors  40  are provided as first sensors that acquire information of temperature of portions in which the first microwave irradiation is performed to the heat generating members  30 , some of the sensors  40  are provided as second sensors that acquire information of temperature of portions in which the second microwave irradiation is performed to the treatment target  2 , and the control unit  50  performs feedback control on the power of microwaves for use in the first microwave irradiation, using the information of temperature acquired by the first sensor, and further performs feedback control on the power of microwaves for use in the second microwave irradiation, using the information of temperature acquired by the second sensor. 
     For example, it is also possible that slits or the like are not formed through the heat generating members  30   a  to  30   c , at the portions thereof between the sensors  40   a  to  40   c  and the treatment target  2 , the sensors  40   a  to  40   c  that are the first sensors acquire information of the temperatures of the heat generating members  30   a  to  30   c , and the control unit  50  performs feedback control on the power of microwaves that are respectively used for irradiation by the first irradiating portions  201   a  to  201   c , using the information of the temperatures of the heat generating members  30   a  to  30   c  respectively acquired by the sensors  40   a  to  40   c , and further performs feedback control on the power of microwaves that are used for irradiation by the second irradiating portions  202   a  to  202   c , using the information of the temperatures of the treatment target  2  in the areas in which the heat generating members  30  are not provided, respectively acquired by the second sensors  40   d  to  40   f . With this configuration, it is possible to properly control the heating of the heat generating members  30  through the first microwave irradiation and the heating of the treatment target  2  through the second microwave irradiation. 
     The conveying unit  60  is a unit that conveys the treatment target  2  in the vessel  10 . The conveying unit  60  may be provided inside the vessel  10  or provided outside the vessel  10 . In this example, as an example, a case is described in which the conveying unit  60  includes a holding portion  62  that rotatably holds a reel  61  around which a precursor fiber that is a treatment target  2  is wound, and a roller  63  that changes the movement direction of the treatment target  2  and sends the treatment target  2  from the inlet  101   a  into the vessel  10 , on the inlet  101   a  side of the vessel  10 , and further includes a roller  64  that changes the movement direction of the treatment target  2  taken out from the outlet  101   b  of the vessel  10 , and a winding portion  65  that takes up the treatment target  2  whose movement direction has been changed by the roller  64 . Note that the conveying unit  60  may be any type of conveying units. If multiple treatment target  2  moves inside the vessel  10 , multiple conveying units  60  may be provided. 
     Next, an operation of the microwave treatment apparatus  1  of this embodiment will be described by way of a specific example. In this example, a case will be described as an example in which flame-resistance treatment on a PAN-based precursor fiber that is the treatment target  2  is performed using the microwave treatment apparatus  1 . Hereinafter, for the sake of convenience of description, a description will be given using the microwave treatment apparatus  1  shown in  FIG.  1   . The treatment target  2  are, for example, a precursor fiber having a width of approximately 5 to 10 mm and a thickness of approximately 1 mm to 2 mm. The microwaves that are used for irradiation have, for example, a frequency of 915 MHz or 2.45 GHz and a power of 6 to 20 KW. 
     First, a PAN-based precursor fiber that is the treatment target  2  is set on the conveying units  60  such that an end thereof enters the vessel  10  from the inlet  101   a , moves through each of the heat generating members  30   a  to  30   c  in the shape of cylinders, and exits the vessel  10  from the outlet  101   b . The conveying units  60  move the treatment target  2  inside the vessel  10 . For example, the conveyance speed of the conveying units  60  is controlled to be a predetermined speed. The microwave irradiation by the first irradiating portions  201   a  to  201   c  and the second irradiating portions  202   a  to  202   c  is started. In this example, it is assumed that the frequencies of microwaves that are used for irradiation by the first irradiating portions  201   a  to  201   c  and the second irradiating portions  202   a  to  202   c  are the same frequency (e.g., 2.45 GHz). The conveyance speed of the conveying units  60  is controlled to be a predetermined speed, for example, by the control unit  50 , an unshown control unit, or the like. The control unit  50  controls the first irradiating portions  201   a  to  201   c  and the second irradiating portions  202   a  to  202   c  such that the microwaves that are used for irradiation by the first irradiating portions  201   a  to  201   c  and the second irradiating portions  202   a  to  202   c  are microwaves with powers individually determined in advance. 
     The portion of the treatment target  2  that enters the vessel  10  from the inlet  101   a  and moves into the heat generating members  30  is heated from the outside by radiant heat from the heat generating members  30  that are configured to generate heat by absorbing part of microwaves used for irradiation by the first irradiating portions  201 , and is directly heated by microwaves that have not been absorbed by the heat generating members  30  and have been transmitted therethrough, out of the microwaves used for irradiation by the first irradiating portions  201 . In this case, for example, assuming that the material and the thickness are set such that the amount of heat generated the heat generating members  30   a  to  30   c  absorbing microwaves used for irradiation by the first irradiating portions  201   a  to  201   c  is sufficiently larger than the amount of heat generated at the treatment target  2  due to microwaves transmitted through the heat generating members  30 , heating of the treatment target  2  in the areas inside the heat generating members  30  is such that heating from the outside by the heat generating members  30  is greater than direct heating with microwaves transmitted through the heat generating members  30 . The power of microwaves used for irradiation by the first irradiating portions  201   a  to  201   c  is subjected to feedback control according to the temperatures of the treatment target  2  respectively acquired by the sensors  40   a  to  40   c , and is controlled such that the treatment target  2  has a temperature in a desired range. 
     When the portion of the treatment target  2  that entered a heat generating member  30  exits to the outside, the portion enters the area in which no heat generating member  30  is provided, the area being provided immediately after the heat generating member  30 , receives microwave irradiation by a second irradiating portion  202  with no heat generating member  30  interposed therebetween, and generates heat due to the microwaves. That is to say, the portion is directly heated by microwaves. In the areas in which the heat generating members  30  are not provided, heating of the treatment target through heat generation at the heat generating members  30 , and thus at direct heating with microwaves is greater than heating from the outside by the heat generating members  30  and the like. The power of microwaves used for irradiation by the second irradiating portions  202   a  to  202   c  is subjected to feedback control according to the temperatures of the treatment target  2  respectively acquired by the sensors  40   d  to  40   f , and is controlled such that the treatment target  2  has a temperature in a desired range. 
     In this manner, the first irradiating portions  201  and the second irradiating portions  202  can perform, in a switchable manner as appropriate, the heating in which heat from the heat generating members  30  is dominant and the heating in which direct heat from microwave irradiation is dominant, to the treatment target  2  that moves inside the vessel  10 . Accordingly, for example, the heating of the treatment target  2  from the outside and direct heating of the treatment target  2  can be performed in a switchable manner as appropriate, and thus it is possible to uniform heat the treatment target  2  such that the heating is not biased either to the heating from the outside or the direct heating. 
     In particular, PAN-based precursor fibers not subjected to flame-resistance treatment are unlikely to absorb microwaves, and thus, even when the first irradiating portions  201  heat the heat generating members  30  through microwave irradiation, the treatment target  2  is directly heated by microwaves transmitted through the heat generating members  30 . Accordingly, it is possible to reduce the time of the second irradiating portions  202  to heat the treatment target  2 . 
     Furthermore, when the temperature of the treatment target  2  reaches a certain temperature through heating, heat generation at the treatment target  2  may reach its peak, and heat may be abruptly generated at the treatment target  2 , which makes it impossible to perform desired treatment due to the treatment target  2  being carbonized, for example. For example, when the temperature of a precursor fiber that is the treatment target  2  reaches a certain temperature through heating, heat generation at the precursor fibers may reach its peak through oxidation, and the precursor fibers may be carbonized. In particular, when the treatment target  2  is heated at high intensity through direct heating in the second microwave irradiation, since the thermal efficiency and the portions at which heat is generated are concentrated at one point, for example, heating shortly progresses from a temperature immediately before the heat generation peak to a temperature corresponding to the heat generation peak. Accordingly, it is difficult to control the heating around the temperature corresponding to the heat generation peak. Thus, in the case in which the treatment target are heated by performing the second microwave irradiation, if the heat generating members  30  are provided such that, when the temperature of the treatment target  2  is about to reach the temperature corresponding to the heat generation peak, the microwave irradiation is switched from the second microwave irradiation to the first microwave irradiation, the heating of the treatment target  2  is switched to heating with radiant heat from the heat generating members  30 , and thus carbonization and the like can be suppressed by suppressing abrupt heating. 
     For example, if the treatment target  2  is moved and heated inside the vessel  10  as in the microwave treatment apparatus  1  as shown in  FIG.  1   , it is possible to know in advance which position the treatment target  2  has reached when the heat generation reaches its peak, based on the movement speed, and the number, the arrangement, the power, and the like of the first irradiating portions  201  and the second irradiating portions  202 . It is also possible that this position is detected through an experiment or the like. Thus, for example, if the heat generating members  30  are provided on the movement path  2   a  of the treatment target  2 , at the position at which the temperature of the treatment target  2  reaches its peak in the heat generation, and the positions before and after that position, and the heat generating members  30  is irradiated with microwaves from the first irradiating portions  201 , it is possible to avoid abrupt heating when heat generation at the treatment target  2  reaches its peak, and to properly treat the treatment target  2 . Furthermore, if the heat generating members  30  are provided or not provided as appropriate at positions not including the position at which the heat generation reaches its peak, the microwave irradiation to the treatment target  2  that moves is switched between the first microwave irradiation and the second microwave irradiation, it is possible to perform uniform heating and desired heating of the treatment target  2 . Note that the temperature corresponding to the heat generation peak of a treatment target can be measured, for example, through TG-TDA measurement (thermogravimetry-differential thermal analysis measurement) or the like. 
     The number of heat generating members  30 , the number and the arrangement of the first irradiating portions  201  and the second irradiating portions  202 , and the like in this specific example are merely an example, and there is no limitation on the number of heat generating members  30 , the number and the arrangement of the first irradiating portions  201  and the second irradiating portions  202 , and the like. 
     As described above, in this embodiment, it is possible to properly treat a treatment target using microwaves, by performing the first microwave irradiation by which a heat generating member is heated and the second microwave irradiation by which a treatment target is heated, in a vessel. For example, it is possible to perform proper heating, by controlling the combination and the ratio between the heating of a treatment target from the outside by a heat generating member caused to generate heat by microwaves, and the direct heating by causing a treatment target to generate heat with microwaves. 
     Furthermore, if the first microwave irradiation is performed at the first irradiating portions  201  and the second microwave irradiation is performed at the second irradiating portions  202 , it is possible to individually control the power of the first microwave irradiation and the power of the second microwave irradiation, to control the heating of treatment targets in detail, and to obtain a treatment result with a high quality. 
     As shown in  FIG.  2 D , it is also possible that a non-transmitting portion  303  that does not transmit microwaves are provided on at least a portion on the treatment target  2  side in the heat generating members  30 .  FIG.  2 D  is a cross-sectional view along the movement direction of the treatment target  2 , illustrating an example of a heat generating member  30  in which the non-transmitting portion  303  is provided inside the heat generating member  30  in the shape of a tube shown in  FIG.  2 A . It is preferable that at least a portion on the treatment target  2  side in the heat generating member  30  is a portion on the treatment target  2  side in the heat generating member  30 , but it may be the entirety on the treatment target  2  side in the heat generating member  30 . For example, at least a portion of the heat generating member  30  on the treatment target  2  side is part of the internal portion of the heat generating member  30  in the shape of a cylinder as shown in  FIG.  2 D . If multiple heat generating members  30  are provided inside the vessel  10 , the portion of the heat generating member  30  on the treatment target  2  side in this case may be the entire face of one or more of the multiple heat generating members  30 . It is preferable that the non-transmitting portion  303  is made of a material that does not transmit microwaves and that has a good heat conductivity. Examples of the material of the non-transmitting portion  303  include graphite and metal. It is also possible that the non-transmitting portion  303  is used instead of part of the support member  302 , and this configuration also may be considered as a configuration in which a portion on the treatment target  2  side in the heat generating member  30  includes the non-transmitting portion  303 . If such a non-transmitting portion  303  is provided, in the portion in which the non-transmitting portion  303  is provided, it is possible to prevent direct heating of the treatment target  2  by preventing the treatment target  2  from being irradiated with microwaves, and to heat the treatment target  2  from the outside through heat generation at the heat generating member  30 . The configuration in which at least a portion in the heat generating member  30  may be provided with a non-transmitting portion applies to other embodiments. 
     In the description above, the thickness of the heat generating member  30  may or may not be a uniform thickness. The state in which the thickness of the heat generating member  30  is not a uniform thickness is a concept that encompasses a state in which there is also a portion with a different thickness. The thickness of the heat generating member  30  may be considered as the thickness of the heating medium  301  of the heat generating member  30 . For example, the thickness of the heat generating member  30  may or may not be a uniform thickness in the longitudinal direction of the heat generating member  30  or the movement direction of the treatment target  2 . For example, if multiple heat generating members  30  are provided inside the vessel  10 , the thickness of one or more of the multiple heat generating members  30  (not all of the heat generating members  30 ) may be a thickness that is different from those of the other heat generating members  30 . In this case, the thickness of each of the multiple heat generating members  30  may be a uniform thickness in the longitudinal direction or the movement direction of the treatment target  2 . The same applies to the description below. 
     For example, in a microwave treatment apparatus as shown in  FIG.  1    as described above, instead of the configuration in which the microwave irradiation that is performed to the movement path  2   a  of the treatment target  2  in the portions in which the heat generating members  30  are not provided is taken as the second microwave irradiation, it is also possible to apply a configuration in which a second heat generating member (not shown) that is thinner than the heat generating members  30  is provided in one or more portions in which the heat generating members  30  are not provided, and the microwave irradiation that is performed from the second irradiating portions  202  to the second heat generating member is taken as the second microwave irradiation. Since the penetration depth of microwaves that are used for irradiation is changed by reducing the thickness of the second heat generating member, if the thickness of the second heat generating member is adjusted, absorption, by the second heat generating member, of microwaves with which the second heat generating member is irradiated can be reduced, the amount of microwaves that are transmitted through the second heat generating member can be increased, and thus the treatment target  2  can be heated at intensity that is higher than that at the second heat generating member. In this case, the treatment target  2  can be heated from the outside as well through heat generation at the second heat generating member. 
     It is also possible that the thickness of one or more of the multiple heat generating members  30  is different from that of the other heat generating members  30 . Accordingly, microwaves that are absorbed by the heat generating members  30  can be changed according to the thickness of the heat generating members  30 , and thus the heating of the heat generating members  30  through the first microwave irradiation, and the ratio of the heating of the heat generating members  30  can be changed. The same applies to the second microwave irradiation using the second heat generating members  30 . The same applies to the description below. 
     Furthermore, in the description above, the material of each heat generating member  30  may be the same material or different materials in the longitudinal direction of the heat generating member  30  or the movement direction of the treatment target  2 . The different materials may be materials with different compositions, components, material proportions, or the like. The state in which the heat generating member  30  is made of different materials is a concept that encompasses a state in which there is also a portion with a different material. The material of the heat generating member  30  in this case may be considered as the material of the heating medium  301  of the heat generating member  30 . For example, if multiple heat generating members  30  are provided inside the vessel  10 , the material of one or more of the multiple heat generating members  30  (not all of the heat generating members  30 ) may be a material that is different from those of the other heat generating members  30 . Three or more heat generating members  30  may be constituted by heat generating members  30  made of three or more different materials. In this case, each material of the multiple heat generating members  30  may be a uniform material. The same applies to the description below. 
     For example, in a microwave treatment apparatus as shown in  FIG.  1    as described above, instead of the configuration in which the microwave irradiation that is performed to the movement path  2   a  of the treatment target  2  in the portions in which the heat generating members  30  are not provided is taken as the second microwave irradiation, it is also possible to apply a configuration in which a second heat generating member (not shown) that is made of a material different from that of the heat generating members  30  is provided in one or more portions in which the heat generating members  30  are not provided, and the microwave irradiation that is performed from the second irradiating portions  202  to the second heat generating member is taken as the second microwave irradiation. Since the penetration depth of microwaves that used for irradiation and the like are changed by changing the composition of the second heat generating member, if the composition of the second heat generating member is selected, absorption, by the second heat generating member, of microwaves with which the second heat generating member is irradiated can be reduced, the amount of microwaves that are transmitted through the second heat generating member can be increased, and thus the treatment target  2  can be heated at intensity that is higher than that at the second heat generating member. In this case, the treatment target  2  can be heated from the outside as well through heat generation at the second heat generating member. 
     It is also possible that the material of one or more of the multiple heat generating members  30  is different from that of the other heat generating members  30 . Accordingly, microwaves that are absorbed by the heat generating members  30  can be changed according to the material of the heat generating members  30 , and thus the heating of the heat generating members  30  through the first microwave irradiation, and the ratio of the heating of the heat generating members  30  can be changed. The same applies to the second microwave irradiation using the second heat generating members  30 . The same applies to the description below. 
     It will be appreciated that the combination of the materials and the thicknesses of the heat generating members  30  and the second heat generating members may be changed. 
     In the description above, the example was described in which the treatment target  2  moves, but it is also possible that the treatment target  2  does not move inside the vessel  10  and the treatment target  2  is let to stand inside the vessel  10 . The same applies to other embodiments. If the movement is not necessary, the conveying units  60  may be omitted. It is also possible that one or more irradiating portions (not shown) included in the microwave irradiating unit  20  each irradiate both of the portions in which the heat generating members  30  are provided and the treatment target  2  in the portions in which the heat generating members  30  are not provided with microwaves. This configuration may be considered as, for example, a configuration in which one or more irradiating portions (not shown) included in the microwave irradiating unit  20  each perform both of the first microwave irradiation and the second microwave irradiation. In this case, the irradiating portions are provided, for example, at positions from which one or more heat generating members  30  and one or more portions in which the heat generating members  30  are not provided on the movement path  2   a  can be irradiated with microwaves. For example, it is also possible that the irradiating portions are provided near the boundary or the like between the heat generating members  30 , and the portions that are adjacent to the heat generating members  30  and are on the movement path  2   a  in which the heat generating members  30  are not provided. Examples of the irradiating portions in this case include irradiating portions similar to the first irradiating portions  201  and the second irradiating portions  202  described above. 
     First Modified Example 
       FIG.  3    is a view showing a first modified example of the microwave treatment apparatus  1  of this embodiment. The microwave treatment apparatus  1  of the first modified example is the microwave treatment apparatus  1  including the heat generating members  30  in the shape of tubes, further including gas supply units  70  that supply oxygen into the heat generating members  30 . Each of the gas supply units  70  includes a supply portion  701  that supplies oxygen, such as an oxygen cylinder or an oxygen generator, a tube  702  through which oxygen is supplied, wherein, for example, one end of the tube  702  is attached to a heat generating member  30  so as to be open inside the heat generating member  30 , and the other end is connected to the supply portion  701 , and a valve  703  that adjusts the amount of oxygen that is supplied, and that is inserted on the path of the tube  702 . There is no limitation on the position at which an end of the tube  702  is attached to the heat generating member  30 . For example, the valve  703  may be controlled by the control unit  50  or the like, or controlled according to an operation by a user or the like. The operation that supplies oxygen in this case is, for example, a concept that encompasses an operation that supplies gas containing oxygen at a higher concentration than gas in the vessel  10  such as air (e.g., gas obtained by adding oxygen to air) or the like. It is also possible that multiple gas supply units  70  use one supply portion  701 . If an external supply portion (not shown) or the like is used instead of the supply portions  701 , the gas supply units  70  do not have to include the supply portions  701 . 
     In order to suppress leakage of oxygen supplied into the heat generating member  30 , to the outside of the heat generating member  30 , two ends through which the treatment target  2  enters and exits the heat generating member  30  may be blocked except for opening portions through which the treatment target  2  can pass. 
     Furthermore, in this example, the case was described in which the gas supply units  70  are respectively provided for all of the multiple heat generating members  30 , but it is also possible that the gas supply units  70  are provided only for some of the multiple heat generating members  30 . 
     If oxygen is supplied by the gas supply units  70  into the heat generating members  30  in this manner, it is possible to properly control treatment that is performed in the microwave treatment apparatus  1 , by controlling the oxygen concentration. For example, it is possible to facilitate shortening the treatment time or performing uniform treatment, by supplying oxygen according to treatment targets. 
     The configuration in which such gas supply units  70  may be provided applies to other embodiments wherein the microwave treatment apparatus includes a heat generating member in the shape of a tube or the like. 
     Furthermore, in the description above, it is also possible that the gas supply units  70  supply predetermined gas other than oxygen. Examples of the predetermined gas include nitrogen gas, noble gas such as argon gas, hydrogen gas, and combination of one or more of these gases. The operation that supplies predetermined gas in this case is, for example, a concept that encompasses an operation that supplies gas containing predetermined gas at a higher concentration than gas in the vessel  10  such as air (e.g., gas obtained by adding predetermined gas to air) or the like. The configuration of the gas supply units  70  is, for example, similar to the configuration described above, except that the gas that is supplied by the supply portion  701  is predetermined gas. If the vessel  10  is filled with gas other than air, the gas that is supplied by the supply portion  701  may be air. The gases that are respectively supplied by the gas supply units  70  connected to different heat generating members  30  may be the same gas, or may be different gases. The gases that are respectively supplied by the gas supply units  70  connected to different heat generating members  30  may be gases at different predetermined concentrations, or may be gases with different composition ratios. 
     Second Modified Example 
       FIGS.  4 A and  4 B  are views showing a second modified example of the microwave treatment apparatus  1  of this embodiment. As shown in  FIGS.  4 A and  4 B , the microwave treatment apparatus  1  of this second modified example includes a member such as a roller or a belt having a heating medium, as a heat generating member, instead of the heat generating members  30 , the heating medium being a member that assists conveyance of the treatment target  2  inside the vessel, having a portion that comes into contact with treatment target  2 , and being configured to generate heat by absorbing microwaves at the portion that comes into contact with the treatment target  2 . In  FIGS.  4 A and  4 B , vessels  10   a  and a vessel  10   b  are vessels corresponding to the vessel  10 . Although a description thereof has been omitted, it is also possible that the microwave treatment apparatus  1  according to the modified example shown in  FIGS.  4 A and  4 B  includes a control unit that is similar to the control unit  50  or sensors that are similar to the sensors  40  shown in  FIG.  1   , and performs feedback control on the power of microwaves and the like according to the output of the sensors. 
     For example, in  FIG.  4 A , the movement path  2   a  is a path that is folded back in the form of multiple layers at multiple rollers  11  that are provided outside the vessels  10   a , and the vessels  10   a  have shapes that cover portions other than the folded portions of the movement path  2   a , and have multiple inlets  101   a  and outlets  101   b  via which the treatment target  2  can enter and exit the vessels  10   a , near the folded portions of the movement path  2   a . There is no limitation on the size and the like of the rollers  11 . In  FIG.  4   , the vessels  10   a  have two cavities  110   a  and  110   b  provided so as to partition the movement path  2   a  into multiple areas, and the multiple inlets  101   a  and the outlets  101   b  are provided as opening portions through which the treatment target  2  can enter and exit the cavities  110   a  and  110   b.    
     In the cavity  110   a , multiple belts  32   a  having heat generating members whose surface includes a heating medium as described above span between rollers  33  so as to hold and be in contact with the treatment target  2  that moves along the movement path  2   a , for example, from above and below. It is assumed that the material of the belts  32   a  is, for example, a material that partially transmit microwaves. Furthermore, the first irradiating portions  201  described above are provided so as to irradiate the portions that are held between the belts  32   a  along the movement path  2   a  with microwaves. For example, the belts  32  move in the movement direction of the movement path  2   a  adjacent thereto, in accordance with the rotation of the rollers  33  by a motor or the like. The belts  32   a  may be belt that are entirely heated by microwaves. For example, a material containing a heating medium as described above and the like may be used as the material of the belts  32   a . Examples of the material of the belts  32   a  include heat-resistant resins, graphite fibers, and the like. The heating medium on the surface of the belts  32   a  may be made of a heating element such as carbon, SiC, a carbon fiber composite material, a metal silicide (e.g., molybdenum silicide or tungsten silicide), or a ceramic material containing a powder or the like of these heating elements, or the like. 
     Furthermore, in the cavity  110   b , multiple belts  32   b  span between rollers  33  so as to hold and be in contact with the treatment target  2  that moves along the movement path  2   a , for example, from above and below. The belts  32   b  is made of a material with high microwave transmission. It is assumed that the surface of the belts  32   b  does not have a heating medium as described above. Furthermore, the second irradiating portions  202  described above are provided so as to irradiate the portions that are held between the belts  32   b  along the movement path  2   a  with microwaves. For example, the belts  32   b  move in the movement direction of the movement path  2   a  adjacent thereto, in accordance with the rotation of the rollers  33  by a motor or the like. 
     The portions of the belts  32   a  and  32   b  holding the treatment target  2  is arranged so as to be in contact with the treatment target  2 , at portions other than those near the rollers  33 . It is also possible that the portions are partially not in contact with the treatment target  2 . 
     The belts  32   a  come into contact with the treatment target  2 , thereby assisting conveyance thereof, and preventing a breakage or non-uniform heating of the treatment target  2  caused when the treatment target  2  is loosened during treatment. In the cavity  110   a , the surface of the belts  32   a  generates heat through microwave irradiation, and heats the treatment target near the belts  32  with radiant heat obtained through the heat generation, the first microwave irradiation as described above is performed by the first irradiating portions  201 , and the portion of the treatment target  2  that comes into contact with the belt  32  can be efficiently heated through heat conduction. 
     Furthermore, as in the case of the belts  32   a , the belts  32   b  come into contact with the treatment target  2 , thereby assisting conveyance thereof, and preventing a breakage or non-uniform heating of the treatment target  2  caused when the treatment target  2  is loosened during treatment. In the cavity  110   b , the surface of the belts  32   b  hardly generates heat through microwave irradiation, and the treatment target  2  is directly heated by microwaves transmitted through the belts  32   b , and thus the second microwave irradiation as described above is performed by the second irradiating portions  202 . 
     It is also possible to omit the belts  32   b  instead of using the belts  32   b , and to perform the second microwave irradiation by which the portions in which the belts  32   b  are omitted are irradiated with microwaves. 
     Furthermore, in this example, the case was described in which the vessel  10  includes two cavities  110   a  and  110   b , it is sufficient that the number of cavities included in the vessel  10  is one or at least two, and there is no limitation on the numbers thereof. Also, there is no limitation on the size and the like of each cavity. There is no limitation on the number of cavities internal portion of which is irradiated with microwaves by the first irradiating portions  201  and cavities internal portion of which is irradiated with microwaves by the second irradiating portions  202 , the order in which the cavities are provided along the movement path  2   a , and the like. The multiple cavities included in the vessel  10  may be arranged so as to be connected to each other, or arranged so as to be separate from each other. For example, multiple cavities that are arranged so as to be connected to each other or multiple cavities that are arranged so as to be separate from each other in order to the above-described treatment on the same treatment target  2  may be considered as one vessel  10 . Also, the treatment target  2  that has been moved from one cavity to the outside may be returned to the same cavity. The configuration in which the vessel  10  may include two or more cavities applies to microwave treatment apparatuses other than the microwave treatment apparatus shown in  FIG.  4 A . 
     Furthermore, the microwave treatment apparatus  1  shown in  FIG.  4 A  may be configured such that a vessel that is not partitioned into multiple cavities is used as the vessel  10 , one or more belts  32   a  and  32   b  as described above are provided in the vessel  10 , one or more first irradiating portions  201  perform first microwave irradiation to the belts  32   a , and one or more second irradiating portions  202  perform second microwave irradiation to the belts  32   b.    
     The above-described shape of the vessels  10   a  and the movement path  2   a  in this case are merely an example, and the shape of the vessel  10  and the movement path of the treatment target  2  may be any shape and any movement path. 
     Furthermore, for example, as shown in  FIG.  4 B , it is also possible that multiple rollers  31   a  whose surface includes a heating medium are arranged such that the surface is in contact with the treatment target  2  that moves along the movement path  2   a , multiple rollers  31   b  whose surface has no heating member, and that hardly absorb microwaves are arranged such that the surface is in contact with the treatment target  2  that moves along the movement path  2   a , at areas that are different from the areas in which the multiple rollers  31   a  are provided, a first irradiating portion  201  that irradiates the areas in which the multiple rollers  31   a  are provided on the movement path  2   a  with microwaves is provided, a second irradiating portion  202  that irradiates the areas in which the rollers  31   b  are provided on the movement path  2   a  with microwaves is provided, and the first irradiating portions  201  and the second irradiating portions  202  perform irradiation with microwaves. The rollers  31   a  may be rollers that are entirely heated by microwaves. For example, a material containing a heating medium as described above and the like may be used as the material of the rollers  31   a . Examples of the material of the rollers  31   a  include heat-resistant resins, ceramics, glasses, graphites, and the like. The heating medium on the surface of the belts  32   a  may be made of a heating element such as carbon, SiC, a carbon fiber composite material, a metal silicide (e.g., molybdenum silicide or tungsten silicide), or a ceramic material containing a powder or the like of these heating elements, or the like. 
     For example, in  FIG.  4 B , the movement path  2   a  is a path that is folded back in the form of multiple layers at multiple rollers  11  that are provided outside the vessel  10   a , and the vessel  10   a  has a shape that covers portions other than the folded portions of the movement path  2   a , and has multiple inlets  101   a  and outlets  101   b  via which the treatment target  2  can enter and exit the vessel, near the folded portions of the movement path  2   a . There is no limitation on the size and the like of the rollers  11 . 
     The multiple rollers  31   a  come into contact with the treatment target  2 , thereby assisting conveyance thereof, and preventing a breakage or non-uniform heating of the treatment target  2  caused when the treatment target  2  is loosened during treatment. The multiple rollers  31   a  are used as heating members described above, their surface generates heat through microwave irradiation, and heats the treatment target near roller  31  with radiant heat obtained through the heat generation, and the portion of the treatment target  2  that comes into contact with roller  31  can be efficiently heated through heat conduction. Accordingly, the microwave irradiation that is performed by the first irradiating portions  201  is the first microwave irradiation. 
     The multiple rollers  31   b  come into contact with the treatment target  2 , thereby assisting conveyance thereof, and preventing a breakage or non-uniform heating of the treatment target  2  caused when the treatment target  2  is loosened during treatment. The multiple rollers  31   b  hardly generate heat through microwave irradiation, and the treatment target  2  is directly heated by microwaves transmitted through the rollers  31   b , and thus the second microwave irradiation as described above is performed by the second irradiating portions  202 . 
     The rollers  31   a  and the rollers  31   b  may or may not be connected to a motor (not shown) or the like and be caused to rotate by themselves. It is sufficient that the number of rollers  31   a  and rollers  31   b  is one or more. 
     It is also possible to omit the rollers  31   b  instead of using the rollers  31   b , and to perform the second microwave irradiation by which the portions in which the rollers  31   b  are omitted are irradiated with microwaves. 
     Also, the arrangement, the arrangement order, and the like of the rollers  31   a  and the rollers  31   b  may be arrangements and arrangement orders other than those described above. There is no limitation on the numbers of rollers  31   a  and rollers  31   b.    
     Furthermore, it is also possible that a vessel including multiple cavities as shown in  FIG.  4 A  may be used instead of the vessel  10   b  shown in  FIG.  4 B . For example, it is also possible that the first irradiating portions  201  or the second irradiating portions  202  are attached to each cavity, the rollers  31   a  are provided in the cavity to which the first irradiating portions  201  are attached, and the rollers  31   b  are provided in the cavity to which the second irradiating portions  202  are attached. 
     Embodiment 2 
       FIG.  5    shows a cross-sectional view that is parallel to the movement direction of a treatment target, illustrating the microwave treatment apparatus in this embodiment ( FIG.  5 A ), a schematic cross-sectional view that is perpendicular to the longitudinal direction that passes through the point Ain  FIG.  5 A  in the heat generating member of the microwave treatment apparatus ( FIG.  5 B ), and a schematic cross-sectional view that is perpendicular to the longitudinal direction that passes through the point B in the heat generating member of the microwave treatment apparatus ( FIG.  5 C ). A microwave treatment apparatus  1   a  of this embodiment performs the first microwave irradiation and the second microwave irradiation, by controlling multiple phases of microwaves that are output by the microwave irradiating unit  21  from different positions. 
     The microwave treatment apparatus  1   a  includes a vessel  10   c , a microwave irradiating unit  21 , a heat generating member  30 , one or at least two sensors  40 , a control unit  51 , and conveying units  60 . 
     The vessel  10   c  is the same as the vessel  10  shown in  FIG.  1    in the foregoing embodiment, except that later-described two or more irradiating portions  203  included in the microwave irradiating unit  21  are attached. the vessel  10   c  may be a vessel as described in the foregoing embodiment, and examples thereof include a vessel including multiple cavities. 
     Hereinafter, a case will be described in which the heat generating member  30  in the shape of one tube is provided along the movement path  2   a  of the treatment target  2  in the vessel  10   c . Note that there may be multiple heat generating members  30 . The heat generating member  30  may be the heat generating member  30  as described in the foregoing embodiment. 
     The microwave irradiating unit  21  includes two or more irradiating portions  203  that perform irradiation with microwaves from different positions. For example, the microwave irradiating unit  21  includes two or more irradiating portions  203  that are attached to the opening portions  102  that are formed at different positions through the wall face of the vessel  10   c , and irradiates the internal portion of the vessel  10   c  with microwaves. At least some of the two or more irradiating portions  203  are irradiating portions  203  that can control the phases of microwaves that used for irradiation. For example, the irradiating portions  203  that can control the phases are each an irradiating portion  203  that includes a microwave oscillator  2001  and a transmitting portion  2002  as described in the foregoing embodiment, further including a phase shifter (not shown) that can control the phases. The microwave oscillators  2001  that are included in the irradiating portions  203  that can control the phases are preferably semiconductor oscillators. The irradiating portions  203  that do not control the phases may be irradiating portions that are similar to the first irradiating portions  201  or the second irradiating portions  202  the foregoing embodiment. Note that the irradiating portions  203  that can control the phases of microwaves that used for irradiation may have any configuration, as long as the phases can be controlled. The operation that controls the phases in this case may be considered as including an operation that sets the phases to a specific phase. 
     The microwave treatment apparatus  1   a  of this embodiment controls the phases of microwaves that are used for irradiation by the two or more irradiating portions  203 , thereby performing first microwave irradiation in which microwaves that are used for irradiation by the two or more irradiating portions  203  are intensified by each other at the heat generating member  30 , and second microwave irradiation in which microwaves that are used for irradiation by the two or more irradiating portions  203  are intensified by each other at the treatment target  2 . For example, the microwave treatment apparatus  1   a  controls the phases of microwaves that are used for irradiation by each of the irradiating portions  203 , using a later-described control unit  51  or the like, thereby performing the first microwave irradiation and the second microwave irradiation. The state in which microwaves are intensified by each other is, for example, a state in which intensities of microwaves are increased by each other. For example, the state in which microwaves are intensified by each other may be a state in which electric field intensities of microwaves are increased by each other, a state in which magnetic field intensities are increased by each other, or a state in which both types of intensities are increased by each other. For example, the microwave treatment apparatus  1   a  controls the phases of microwaves that are used for irradiation by the two or more irradiating portions, using the control unit  51  or the like, thereby causing the phases of microwaves used for irradiation by the irradiating portions to be intensified by each other at a given position through an interference. For example, the microwave treatment apparatus  1   a  controls the phases of microwaves that are used for irradiation by the two or more irradiating portions, using the control unit  51  or the like, thereby causing microwaves used for irradiation by the irradiating portions to have the same phase at a given position, so as to be intensified by each other. The operation that causes microwaves to be intensified by each other at a given position may be considered as an operation that causes microwaves to be concentrated at a given position. The microwave treatment apparatus  1   a  causes microwaves not to be intensified by each other at a given position through an interference, thereby causing the microwaves not to be intensified by each other. The microwave treatment apparatus  1   a  causes microwaves not to have the same phase at a given position, for example, to have opposite phases, so as not to be intensified by each other. If all microwaves that are used for irradiation by the irradiating portions  203  have the same frequency, for example, it is possible to cause microwaves used for irradiation from multiple positions to be intensified by each other at a given position in the following manner: the distance between the given position and each position from which irradiation with microwaves is performed is divided by the microwave wavelength, a remainder thereof is further divided by the microwave wavelength and multiplied by 2π to obtain a value, and the phase is advance by that value relative to the reference phase. Note that there is no limitation on the manner how microwave phases are controlled to cause the microwaves to have the same phase at a given position. The processing that controls microwave phases, thereby increasing intensity of microwaves at a given position is known, for example, in JP 2017-212237A and the like, and thus a detailed description thereof has been omitted. 
     The first microwave irradiation that is performed by controlling the phases of microwaves that are used for irradiation by the two or more irradiating portions  203  is, for example, performing irradiation from multiple positions in the vessel  10   c , with microwaves whose phases are controlled such that microwaves are not intensified by each other at a given position on the treatment target  2 , and microwaves are intensified by each other at one or more portions on the heat generating member  30 , around the given position. The one or more portions around the given position on the treatment target  2  are one or more portions that are in a direction that is perpendicular to the extending direction of the treatment target  2  or the movement direction of the treatment target  2 . The given position on the treatment target  2  is, for example, a given position on the movement path  2   a  of the treatment target  2 . The same applies to the description below. The first microwave irradiation in this case may be, for example, performing irradiation from multiple positions in the vessel  10   c , with microwaves whose phases are controlled such that the intensity of microwaves at one or more portions on the heat generating member  30 , around the given position, is higher than the intensity of microwaves at the given position on the treatment target  2 . The one or more portions around the given position are, for example, one or more portions on the heat generating member  30 , the portions intersecting a virtual face that is perpendicular to the traveling direction of the movement path  2   a , at the given position on the movement path  2   a  of the treatment target  2 . The first microwave irradiation in this case may be, for example, performing irradiation from multiple positions in the vessel  10   c , with microwaves whose phases are controlled such that microwaves are intensified by each other at the given position on the treatment target  2 , and performing irradiation from multiple positions in the vessel  10   c  that are different from the above-mentioned multiple positions, with microwaves whose phases are controlled such that microwaves are intensified by each other at one or more portions on the heat generating member  30 , around the given position, wherein the power of microwaves that are output with their phases being controlled such that the microwaves are intensified by each other at the heat generating member  30  is set higher than the power of microwaves that are output with their phases being controlled such that the microwaves are intensified by each other at the treatment target  2 . 
     Furthermore, the second microwave irradiation that is performed by controlling the phases of microwaves that are used for irradiation by the two or more irradiating portions  203  is, for example, performing irradiation from multiple positions in the vessel  10   c , with microwaves whose phases are controlled such that microwaves are intensified by each other at a given position on the treatment target  2 , and microwaves are not intensified by each other at the heat generating member  30 , around the given position. The second microwave irradiation in this case may be, for example, performing irradiation from multiple positions in the vessel  10   c , with microwaves whose phases are controlled such that the intensity of microwaves at the given position on the treatment target  2  is higher than the intensity of microwaves at one or more portions on the heat generating member  30 , around the given position. The second microwave irradiation in this case may be, for example, performing irradiation from multiple positions in the vessel  10   c , with microwaves whose phases are controlled such that microwaves are intensified by each other at the given position on the treatment target  2 , and performing irradiation from multiple positions in the vessel  10   c  that are different from the above-mentioned multiple positions, with microwaves whose phases are controlled such that microwaves are intensified by each other at one or more portions on the heat generating member  30 , around the given position, wherein the power of microwaves that are output with their phases being controlled such that the microwaves are intensified by each other at the treatment target  2  is set higher than the power of microwaves that are output with their phases being controlled such that the microwaves are intensified by each other at the heat generating member  30 . 
     There is no limitation on the positions at which microwaves are intensified by each other by performing the first microwave irradiation in this case, the number of positions at which microwaves are intensified by each other, the positions at which microwaves are intensified by each other by performing the second microwave irradiation, the number of positions at which microwaves are intensified by each other, or the like. It is also possible that the positions and the number of positions are set as appropriate according to results of experiments or simulations that are performed on the treatment target  2  or the like. 
     Furthermore, the two or more irradiating portions  203  that perform the first microwave irradiation and the two or more irradiating portions  203  that perform second microwave irradiation may be the same irradiating portions  203  or may be different irradiating portions  203 , or only some of them are the same irradiating portions  203 . Also, microwaves that are used for irradiation by the two or more irradiating portions  203  that perform the first microwave irradiation and microwaves that are used for irradiation by the two or more irradiating portions  203  that perform second microwave irradiation may be the same frequency, or may be different frequencies. 
     The one or at least two sensors  40  are, for example, the same as the sensors in the foregoing embodiment. The sensors  40  are provided, for example, near the positions at which the first microwave irradiation is performed or near the positions at which the second microwave irradiation is performed in the vessel  10   c.    
     The conveying units  60  are the same as those in the foregoing embodiment, and thus a detailed description thereof has been omitted. 
     The control unit  51  controls the phases of microwaves that are used for irradiation by the microwave irradiating unit  21  from multiple positions. The operation that controls the phases of microwaves that are used for irradiation by multiple positions may be considered as a concept that encompasses an operation that does not control one or more microwave phases serving as a reference, but controls other microwave phases. As described above, the control unit  51  controls the phases of microwaves that are used for irradiation by the microwave irradiating unit  21  such that the first microwave irradiation is performed at one or at least two given positions on the movement path  2   a  of the treatment target  2 , and the second microwave irradiation is performed at one or at least two given positions on the movement path  2   a  of the treatment target  2 , the positions being different from the above-mentioned positions at which the first microwave irradiation is performed. For example, the phases of microwaves that are respectively used for irradiation by the multiple irradiating portions  203  are controlled such that the first microwave irradiation and the second microwave irradiation are performed in this manner. The control unit  51  may individually control the power of microwaves that are used for irradiation by the microwave irradiating unit  21  from multiple positions. For example, the control unit  51  may individually control the power of microwaves that are used for irradiation by the irradiating portions  203 . For example, the control unit  51  performs feedback control on the power of the irradiating portions  203  that perform the first microwave irradiation at a given position, according to the information of temperature or the like output by the sensors  40  provided near the given position. For example, the control unit  51  performs feedback control on the power of the irradiating portions  203  that perform the second microwave irradiation at a given position, according to the information of temperature or the like output by the sensors  40  provided near the given position. Note that it is also possible to perform control other than the feedback control. 
     If the phases do not have to be changed after the phases of the irradiating portions  203  are once set such that microwaves are intensified by each other at one or at least two given positions, or if the phases of the irradiating portions  203  are manually set, for example, the control unit  51  does not have to control the phases of microwaves that are used for irradiation by the irradiating portions  203 , and the control unit for controlling the phases does not have to be provided. 
     Next, an operation of the microwave treatment apparatus  1   a  of this embodiment will be described by way of a specific example. In this example, a case will be described as an example in which flame-resistance treatment on a PAN-based precursor fiber that is the treatment target  2  is performed using the microwave treatment apparatus  1   a . Hereinafter, for the sake of convenience of description, a description will be given using the microwave treatment apparatus  1   a  shown in  FIG.  5 A . 
     In this example, it is assumed that the treatment target  2  is moved by the conveying units  60  along the movement path  2   a , the first microwave irradiation is performed on the point A on the movement path  2   a  of the treatment target  2  shown in  FIG.  5   , and the second microwave irradiation is performed on the point B. Specifically, the control unit  51  controls the multiple irradiating portions  203 , thereby causing the multiple irradiating portions  203  to perform irradiation with microwaves whose phases are controlled such that microwaves are not intensified by each other at the point A on the movement path  2   a  of the treatment target  2 , and microwaves are intensified by each other at one or more portions on the heat generating member  30 , around the point A. In this case, for example, it is assumed that irradiation with microwaves is performed such that the microwaves are intensified by each other at the point A from those attached on the inlet  101   a  side, corresponding to a half of the multiple irradiating portions  203 . That is to say, it is assumed that the first microwave irradiation is performed by those attached on the inlet  101   a  side, corresponding to a half of the multiple irradiating portions  203 . The control unit  51  controls the multiple irradiating portions  203 , thereby causing the multiple irradiating portions  203  to perform irradiation with microwaves whose phases are controlled such that microwaves are intensified by each other at the point B on the movement path  2   a  of the treatment target  2 , and microwaves are not intensified by each other at one or more portions on the heat generating member  30 , around the point B. In this case, for example, it is assumed that irradiation with microwaves is performed such that the microwaves are intensified by each other at the point B from those attached on the outlet  101   b  side, corresponding to a half of the multiple irradiating portions  203 . That is to say, it is assumed that the second microwave irradiation is performed by those attached on the outlet  101   b  side, corresponding to a half of the multiple irradiating portions  203 . It is also possible that the first microwave irradiation and the second microwave irradiation are performed also at portions other than the points A and B above. 
     At the point A, the first microwave irradiation is performed, and thus points  35  at which microwaves are intensified by each other appear at multiple points (e.g., four points in this example) on the heat generating member  30  as shown in  FIG.  5 B . The heat generating member  30  generates heat due to the microwaves that are intensified by each other at the points  35 , and the treatment target  2  is heated from the outside by radiant heat of the heat generating member  30 . At the point A, the treatment target  2  is directly heated as well by microwaves, unless multiple microwaves that are used for irradiation by the multiple irradiating portions  203  completely cancel each other to be “0”. However, this is not a point at which multiple microwaves are intensified by each other, and thus the amount of heat generated is small. 
     Furthermore, at the point B, the second microwave irradiation is performed, and thus a point  35  at which microwaves are intensified by each other appears at the treatment target  2  as shown in  FIG.  5 C . The treatment target  2  is directly heated by the microwaves that are intensified by each other at the points  35 . Around the point B, the heat generating member  30  generates heat as well due to the microwaves, unless multiple microwaves that are used for irradiation by the multiple irradiating portions  203  are completely cancel each other to be “0”, and the treatment target  2  is heated from the outside as well through heat generation. However, this is not a point at which multiple microwaves are intensified by each other, and thus the amount of heat generated is small. 
     If the control unit  51  performs feedback control on the multiple irradiating portions  203  at which the first microwave irradiation is performed onto the point A, according to the temperature acquired by the sensors  40  provided near the point A, it is possible to increase or decrease the power of microwaves that are intensified by each other at the heat generating member  30  around the point A, and to perform heating at a desired temperature to the treatment target  2  at the point A. Also, if the control unit  51  performs feedback control on the multiple irradiating portions  203  at which the second microwave irradiation is performed onto the point B, according to the temperature acquired by the sensors  40  provided near the point B, it is possible to increase or decrease the power of microwaves that are intensified by each other at the point B on the treatment target  2 , and to perform heating at a desired temperature to the treatment target  2  at the point B. 
     For example, as described in the foregoing embodiment, at or near the position corresponding to the heat generation peak at the treatment target  2 , if the first microwave irradiation is performed while controlling the phases such that microwaves are intensified by each other at the heat generating member  30  therearound, and are not intensified by each other at the treatment target  2  in a way similar to that at the point A described above, it is possible to properly treat the treatment target  2  while avoiding abrupt heating when the treatment target  2  reaches its heat generation peak. Also, at other positions, for example, if irradiation with microwaves is performed such that the microwaves are intensified by each other at the treatment target  2 , it is possible to efficiently heat the treatment target  2  mainly through direct heating with microwaves, and to improve the treatment speed. At other positions, for example, if irradiation with microwaves is performed such that the microwaves are intensified by each other at the treatment target  2  or such that the microwaves are intensified by each other at the heat generating member  30 , it is possible to properly perform, in a switchable manner, the first microwave irradiation and the second microwave irradiation on the treatment target  2  that moves, and to perform uniform heating and desired heating of the treatment target  2 . 
     The arrangement of the multiple irradiating portions  203  in this specific example is merely an example, and there is no limitation on the arrangement or the number of the multiple irradiating portions  203 . 
     Furthermore, there is no limitation on the set number or the arrangement of each of points such as the point A at which microwaves are intensified by each other at the heat generating member  30 , points such as the point B at which microwaves are intensified by each other at the treatment target  2 , and points at which microwaves are intensified by each other at both of the heat generating member  30  and the treatment target  2 , on the movement path  2   a  of the treatment target  2  in the vessel  10   c . In the microwave treatment apparatus  1   a , for example, with respect to the movement path  2   a , it is sufficient that at least one or more points at which microwaves are intensified by each other at the heat generating member  30 , and at least one or more points at which microwaves are intensified by each other at the treatment target  2  are set on the movement path  2   a.    
     As described above, according to this embodiment, it is possible to properly treat the treatment target  2  using microwaves, by controlling multiple phases of microwaves that are used for irradiation by the microwave irradiating unit  21  from different positions, thereby performing the first microwave irradiation in which two or more microwaves are intensified by each other at the heat generating member  30  and the second microwave irradiation in which two or more microwaves are intensified by each other at the treatment target  2 . For example, it is possible to perform proper heating, by controlling the combination and the ratio between heating of a treatment target from the outside by a heat generating member caused to generate heat by microwaves, and the directly heating the treatment target with microwaves. 
     In the description above, feedback control on the power of microwaves that used for irradiation is performed according to the information of temperature and the like acquired by the sensors  40 , but it is also possible to control the heating of the treatment target  2 , by controlling control the phases of microwaves that are used for irradiation by the microwave irradiating unit  21 , according to the information of temperature acquired by one or more sensors  40 , thereby moving the positions at which microwaves are intensified by each other through the first microwave irradiation or the second microwave irradiation along the movement path  2   a  of the treatment target  2 . For example, in the description above, when the temperature at the point B acquired by the sensor  40  is high, it is also possible to delay the time to perform heating through the second microwave irradiation, by moving the position of the point B. 
     Furthermore, in the description above, it is also possible that the first microwave irradiation by which irradiation with microwaves is performed such that the microwaves are intensified by each other at the heat generating member  30  and the second microwave irradiation by which irradiation with microwaves is performed such that the microwaves are intensified by each other at the treatment target  2  are simultaneously performed at the same position on the movement path  2   a  of the treatment target  2 . In this case, the power of microwaves in the first microwave irradiation and the power of microwaves in the second microwave irradiation may be different from each other. 
     Furthermore, in the foregoing embodiment, the case was described as an example in which the treatment target  2  moves inside the vessel  10   c , but it is also possible that the treatment target  2  does not move inside the vessel  10   c , and the positions at which the heat generating member  30  is heated and the positions at which the treatment target  2  is directly heated are changed over time, by controlling multiple phases of microwaves with which the internal portion of the vessel  10   c  is irradiated, thereby changing over time the positions at which microwaves are intensified by each other through the first microwave irradiation at the heat generating member  30 , and the positions at which microwaves are intensified by each other through the second microwave irradiation at the treatment target  2 . With this configuration, for example, it is possible to perform proper heating of the treatment target  2 . 
     In the foregoing embodiment, if the phases of microwaves that are used for irradiation by the microwave irradiating unit  21  from the multiple irradiating portions  203  are controlled, it is preferable to design the vessel  10   c  such that a first microwave irradiation position at which microwaves that are used for irradiation by the irradiating portions  203  are intensified in the heat generating member  30 , and a second microwave irradiation position at which microwaves that are used for irradiation by the irradiating portions  203  are intensified in the treatment target  2  are provided along the movement path  2   a  of the treatment target  2 . 
     Furthermore, in the foregoing embodiment, it is also possible that the phases of microwaves that are used for irradiation by the microwave irradiating unit  21  from the multiple irradiating portions  203  are not controlled. For example, if the microwave irradiating unit  21  includes one or more irradiating portions  203  that perform irradiation with microwaves, it is also possible to, instead of controlling the phases of microwaves that are used for irradiation by each of the irradiating portions  203 , design the vessel  10   c  such that a first microwave irradiation position at which microwaves that are used for irradiation by the irradiating portions  203  are intensified in the heat generating member  30 , and a second microwave irradiation position at which microwaves that are used for irradiation by the irradiating portions  203  are intensified in the treatment target  2  are provided along the movement path  2   a  of the treatment target  2 . 
     Modified Examples 
     In the microwave treatment apparatus  1   a  of Embodiment 2, it is also possible that one or at least two heat generating members  30  are provided inside the vessel  10   c  along part of the movement path  2   a  of the treatment target  2  as in Embodiment 1 described above, and the control unit  51  or the like controls the phases of microwaves that are respectively used for irradiation by two or more irradiating portions  203  that perform irradiation with microwaves from different positions, thereby providing a first microwave irradiation position at which microwaves that are used for irradiation by the irradiating portions  203  are intensified in the heat generating members  30 , a second microwave irradiation position at which microwaves that are used for irradiation by the irradiating portions  203  are intensified in the treatment target in a portion in which the heat generating member is not provided, and a third microwave irradiation position at which microwaves that are used for irradiation by the irradiating portions  203  are intensified in the treatment target in a portion in which the heat generating member is provided. 
       FIG.  7 A  is a schematic cross-sectional view that is parallel to the movement direction of a treatment target, illustrating an example of a modified example of the microwave treatment apparatus  1   a . This microwave treatment apparatus  1   a  is the microwave treatment apparatus  1   a  of Embodiment 2, wherein heat generating members  30   d  and  30   e  that are two heat generating members are provided inside the vessel  10   c  at a predetermined interval along part of the movement path  2   a  of the treatment target  2  so as to cover the treatment target  2 , and the microwave irradiating unit  21  includes, as the two or more irradiating portions  203 , three irradiating portions  203   a , three irradiating portions  203   b , and three irradiating portions  203   c  that perform irradiation with microwaves from different positions. The three irradiating portions  203   a , the three irradiating portions  203   b , and the three irradiating portions  203   c  are each attached to the vessel  10   c  in a way similar to that of the irradiating portions  203  described above. The heat generating members  30   d  and  30   e  may be considered as being provided such that an area in which no heat generating member is provided is interposed therebetween. In this example, a case is shown in which the three irradiating portions  203   a , the three irradiating portions  203   b , and the three irradiating portions  203   c  are provided along the movement path  2   a  of the treatment target  2  sequentially from the inlet side of the vessel  10   c , but the arrangement is not limited to this. For example, the irradiating portions  203  are positioned such that microwaves can be intensified by each other at one or more given positions by controlling the phases. In the drawing, the sensors, the control unit, and the like are not shown. 
       FIGS.  7 B to  7 D  are schematic views showing the heat generating members  30   d  and  30   e  and the vicinity thereof in the microwave treatment apparatus shown in  FIG.  7 A , illustrating a position at which microwaves are intensified. 
     For example, in the microwave treatment apparatus  1   a  shown in  FIG.  7 A , the phases of microwaves that are respectively used for irradiation by the three irradiating portions  203   a  are controlled such that the microwaves are intensified at a position  400   a  at which the heat generating member  30   d  is provided in the movement direction of the treatment target  2 , the phases of microwaves that are respectively used for irradiation by the three irradiating portions  203   b  are controlled such that the microwaves are intensified in the treatment target  2  at a position  400   b  between the heat generating members  30   d  and  30   e  at which the heat generating member  30   e  is not provided in the movement direction of the treatment target  2 , and the phases of microwaves that are respectively used for irradiation by the three irradiating portions  203   c  are controlled such that the microwaves are intensified at a portion of the treatment target that is located inside the heat generating member  30  at a position  400   c  at which the heat generating member  30   d  is provided in the movement direction of the treatment target  2 . In this example, it is assumed that the position  400   a  and the position  400   c  are different positions in the direction that is along the movement path  2   a  of the treatment target  2 . In this example, the phases are controlled such that the position  400   c  is provided so as to be closer to the heat generating member  30   e  than the position  400   a  is, but it is also possible that the phases are controlled such that the position  400   a  is provided so as to be closer to the heat generating member  30   e  than the position  400   c  is. The phases are controlled, for example, using a control unit that is similar to the control unit  51 . 
     When the microwave irradiating unit  21  performs irradiation with microwaves as described above, as shown in  FIG.  7 B , the position  400   a , the position  400   b , and the position  400   c  are positions at which the intensity of microwaves is high. Accordingly, the heat generating member  30   d  is heated at high intensity at the position  400   a , and the treatment target  2  is heated at high intensity at the position  400   b  and the position  400   c . It is assumed that the position  400   c  is a position that overlaps the treatment target  2  inside the heat generating member  30   d . In this case, the position  400   a  corresponds to the first microwave irradiation position, the position  400   b  corresponds to the second microwave irradiation position, and the position  400   c  and the vicinity thereof correspond to the third microwave irradiation position. These positions may be considered as areas. 
     In this manner, if the positions at which microwaves are intensified are set to a portion in which the heat generating member  30  is provided, the treatment target  2  in a portion in which the heat generating member  30  is not provided, and the treatment target  2  in a portion in which the heat generating member  30  is provided (e.g., a portion of the treatment target  2  that is located inside the heat generating member  30 ), for example, it is possible to perform desired heating of the treatment target  2 . 
     In the description above, it is also possible to perform irradiation with microwaves such that the position  400   a  that is the first microwave irradiation position and the position  400   c  that is the third microwave irradiation position are the same position in the direction that is along the movement path  2   a  of the treatment target as shown in  FIG.  7 C , by controlling the phases of microwaves that are respectively used for irradiation by the three irradiating portions  203   a  and the phases of microwaves that are respectively used for irradiation by the three irradiating portions  203   c.    
     Furthermore, in the description above, it is also possible to arrange the position  400   a  that is the first microwave irradiation position and the position  400   c  that is the third microwave irradiation position, in portions in which different heat generating members  30  are provided, by controlling each of the phases of microwaves that are respectively used for irradiation by the three irradiating portions  203  and the phases of microwaves that are respectively used for irradiation by the three irradiating portions  203   c . For example, as shown in  FIG.  7 D , it is also possible that the position  400   a  that is the first microwave irradiation position is provided at the heat generating member  30   d , and the position  400   c  that is the third microwave irradiation position is provided at the heat generating member  30   e.    
     In the description above, the case was described as an example in which the number of heat generating members  30  is two, but it is sufficient that the number of heat generating members  30  is one or more, if the first microwave irradiation position and the third microwave irradiation position are provided in a portion in which the same heat generating member  30  is provided as shown in  FIGS.  7 B and  7 C . The lengths, materials, and the like of at least some of the two or more heat generating members  30  may be the same or different from each other. 
     Furthermore, it is sufficient that the number of heat generating members  30  is two or more, if the first microwave irradiation position and the third microwave irradiation position are provided in portions in which different heat generating members  30  are provided as shown in  FIG.  7 D . 
     Furthermore, the heat generating member  30  in which the first microwave irradiation position is provided and the area of the treatment target  2  in which no heat generating member is provided and in which the second microwave irradiation position is provided, may be adjacent to each other as shown in  FIG.  7 B , or may not be adjacent to each other. 
     Furthermore, if the position  400   a  that is the first microwave irradiation position and the position  400   c  that is the third microwave irradiation position are provided in portions in which different heat generating members  30  are provided, the first microwave irradiation position and the third microwave irradiation position may be heat generating members  30  that are adjacent to each other between which only one area in which no heat generating member is provided is interposed, or may be heat generating members  30  that are adjacent to each other between which two or more areas in which no heat generating member is provided are interposed. 
     Furthermore, there is no limitation on the number of irradiating portions  203   a , as long as it is two or more. The same applies to the irradiating portions  203   b  and  203   c . It is also possible that at least some of two or more irradiating portions  203   a  and two or more irradiating portions  203   b  are realized by the same irradiating portion. That is to say, it is also possible that at least some of two or more irradiating portions  203   a  are used as at least some of two or more irradiating portions  203   b , and at least some of the irradiating portions  203   a  and at least some of the irradiating portions  203   b  are shared. The same applies to at least some of two or more irradiating portions  203   a  and two or more irradiating portions  203   c , and at least some of two or more irradiating portions  203   b  and two or more irradiating portions  203   c . In a similar manner, it is also possible that at least some of two or more irradiating portions  203   a , two or more irradiating portions  203   b , and two or more irradiating portions  203   c  are realized by the same irradiating portion. That is to say, it is also possible that at least some of two or more irradiating portions  203   a  are used as at least some of two or more irradiating portions  203   b , and also as at least some of two or more irradiating portions  203   c . It is also possible that the microwave irradiating unit  21  includes multiple sets each consisting of two or more first irradiating portions  203   a . The same applies to the second irradiating portions  203   b  and the third irradiating portions  203   c.    
     Furthermore, it is also possible that the microwave irradiating unit  21  performs irradiation with microwaves whose phases are controlled such that multiple first microwave irradiation positions are provided in the microwave treatment apparatus  1   a . The same applies to the second and third microwave irradiation positions. It is also possible that the microwave irradiating unit  21  performs irradiation with microwaves whose phases are controlled such that multiple first microwave irradiation positions are provided in one heat generating member  30 . The same applies to the second and third microwave irradiation positions. 
     In the description above, the first to third microwave irradiation positions are provided as described above by controlling the phases of microwaves that are used for irradiation by each of the irradiating portions  203 , but it is also possible to arrange the first to third microwave irradiation positions as described above by designing the vessel  10   c  and the like. In this case, it is sufficient that the number of irradiating portions  203  included in the microwave irradiating unit  21  is one or more. The designing the vessel  10   c  and the like may be considered as designing a cavity and the like that are irradiated with microwaves. The designing the vessel  10   c  and the like may be considered as designing also including the arrangement of the irradiating portions  203  and the like. 
     Embodiment 3 
       FIG.  6    shows a cross-sectional view that is parallel to the movement direction of a treatment target, illustrating the microwave treatment apparatus in this embodiment ( FIG.  6 A ), a schematic cross-sectional view that is perpendicular to the longitudinal direction that passes through the point Ain  FIG.  6 A  ( FIG.  6 B ), a schematic cross-sectional view that is perpendicular to the longitudinal direction that passes through the point B ( FIG.  6 C ), and a schematic cross-sectional view that is perpendicular to the longitudinal direction that passes through the point C ( FIG.  6 D ). A microwave treatment apparatus  1   b  of this embodiment causes the microwave irradiating unit  22  to perform irradiation with microwaves with different frequencies, thereby performing the first microwave irradiation and the second microwave irradiation. 
     The microwave treatment apparatus  1   b  includes a vessel  10   d , a microwave irradiating unit  22 , a heat generating member  30 , one or at least two sensors  40 , a control unit  52 , and conveying units  60 . 
     The vessel  10   d  is the same as the vessel  10  shown in  FIG.  1    in the foregoing embodiment, except that irradiating portions included in the microwave irradiating unit  22  are attached. The vessel  10   d  may be a vessel as described in the foregoing embodiment, and examples thereof include a vessel including multiple cavities. 
     Hereinafter, a case will be described in which the heat generating member  30  in the shape of one tube is provided along the movement path  2   a  of the treatment target  2  in the vessel  10   d . Note that there may be multiple heat generating members  30 . The heat generating member  30  may be the heat generating member  30  as described in the foregoing embodiment. 
     The microwave irradiating unit  22  can perform irradiation with microwaves with different frequencies, and perform the first microwave irradiation and the second microwave irradiation as described above by performing irradiation with microwaves with different frequencies. For example, the microwave irradiating unit  22  performs first microwave irradiation by which irradiation with microwaves is performed with a frequency at which heat generation at the heat generating member  30  is greater than heat generation at the treatment target  2 , and second microwave irradiation by which irradiation with microwaves is performed with a frequency at which heat generation at the treatment target  2  is greater than heat generation at the heat generating member  30 . For example, the microwave irradiating unit  22  performs first microwave irradiation by which irradiation with microwaves is performed with a frequency at which microwaves absorbed by the heat generating member  30  are greater than microwaves transmitted through the heat generating member  30  and second microwave irradiation by which irradiation with microwaves is performed with a frequency at which microwaves absorbed by the heat generating member  30  are less than microwaves transmitted through the heat generating member  30 . The frequency of microwaves that are used for irradiation in the first microwave irradiation by the microwave irradiating unit  22  is hereinafter referred to as a first frequency. The frequency of microwaves that are used for irradiation in the second microwave irradiation by the microwave irradiating unit  22  is hereinafter referred to as a second frequency. 
     For example, microwaves that are transmitted through the heat generating member  30  depend on the frequency of microwaves that are used for irradiation. For example, if a heat generating member  30  with a complex permittivity of ε′=100 and ε″=10 is used, the half-power depth at which the electric power of microwaves that have entered the heat generating member  30  is halved is 36.3 mm if the frequency is 915 MHz, and 13.6 mm if the frequency is 2.45 GHz. Thus, in the case in which the thickness of the heat generating member  30  is set to a proper thickness, for example, if microwaves at 2.45 GHz are used for irradiation, more than half of the microwaves, preferably a large portion thereof is absorbed by the heat generating member  30 , and thus the microwaves do not reach the treatment target  2  that is a precursor fiber of a carbon fiber or the like. Meanwhile, if microwaves at 915 MHz are used for irradiation, more than half of the microwaves that are used for irradiation, preferably a large portion thereof is transmitted through the heat generating member  30 , and thus the precursor fiber of a carbon fiber can be irradiated with the microwaves. The thickness of the heat generating member  30  in this case may be considered as the thickness of the heating medium  301  of the heat generating member  30 . Thus, in the first microwave irradiation, if the heat generating member  30  is irradiated with microwaves with a frequency corresponding to a half-power depth at which microwaves absorbed by the heat generating member  30  are greater than microwaves transmitted through the heat generating member  30 , the heat generating member  30  can be heated in the first microwave irradiation, and, in the second microwave irradiation, if the heat generating member  30  is irradiated with microwaves with a frequency corresponding to a half-power depth at which microwaves absorbed by the heat generating member  30  are less than microwaves transmitted through the heat generating member, the treatment target  2  is irradiated with the microwaves transmitted through the heat generating member  30 , and thus the treatment target  2  inside the heat generating member can be heated in the second microwave irradiation. 
     For example, if the heat generating member  30  (e.g., the heating medium  301  of the heat generating member  30 ) is made of aluminum with an electrical resistivity of 2.8×10 −8  Ωm, the skin depth at which the electric field strength of microwaves that have entered the heat generating member  30  is 1/e is 2.2 μm if the frequency is 915 MHz, and 1.3 μm if the frequency is 2.45 GHz. Thus, if the thickness of the heat generating member  30  (e.g., the thickness of the heating medium  301  of the heat generating member  30 ) is controlled to, for example, in the unit of approximately hundred nanometers, in the first microwave irradiation with a first frequency of 2.45 GHz, a large portion of microwaves is absorbed by the heat generating member  30 , and thus the microwaves can be prevented from reaching the treatment target  2  that is a precursor of a carbon fiber or the like, whereas, in the second microwave irradiation with a second frequency of 915 MHz, a large portion of microwaves is not absorbed by the heat generating member  30 , the treatment target  2  is irradiated with the microwaves, and thus the treatment target  2  can be heated. In the above-described complex permittivity, the imaginary part ε″ may be also referred to as a relative dielectric loss. 
     For example, when the treatment target  2  moves, the microwave irradiating unit  22  may perform the first microwave irradiation and the second microwave irradiation to different positions on the movement path  2   a  of the treatment target  2 . The microwave irradiating unit  22  may simultaneously perform the first microwave irradiation and the second microwave irradiation to the same position on the movement path  2   a  of the treatment target  2 . The microwave irradiating unit  22  may perform, in a switchable manner, the first microwave irradiation and the second microwave irradiation to the same position on the movement path  2   a  of the treatment target  2 . The microwave irradiating unit  22  may change the power of microwaves that are used for irradiation at each frequency. 
     For example, it is also possible that the microwave irradiating unit  22  includes one or more irradiating portions (not shown) that can change the frequency of microwaves that are used for irradiation, and perform, in a switchable manner, the first microwave irradiation and the second microwave irradiation by changing the frequency of microwaves that are used for irradiation. It is also possible that the microwave irradiating unit  22  includes one or more irradiating portions (hereinafter, referred to as first frequency irradiating portions  204 ) that perform irradiation with microwaves with the first frequency for performing the first microwave irradiation and one or more irradiating portions (hereinafter, referred to as second frequency irradiating portions  205 ) that perform irradiation with microwaves with the second frequency that is different from the first frequency, for performing the second microwave irradiation, and perform irradiation with microwaves with different frequencies used for irradiation by these irradiating portions, thereby performing the first microwave irradiation and the second microwave irradiation. Hereinafter, in this embodiment, a case will be described as an example in which the first microwave irradiation is performed using one or more first frequency irradiating portions  204  and the second microwave irradiation is performed using one or more second frequency irradiating portions  205 . 
     For example, the first frequency irradiating portions  204  and the second frequency irradiating portions  205  are attached to the opening portions  102  that are formed at different positions through the wall face of the vessel  10   d , and irradiate the internal portion of the vessel  10   d  with microwaves. The first frequency irradiating portions  204  and the second frequency irradiating portions  205  may be provided such that different positions on the movement path of the treatment target  2  are irradiated with microwaves or may be provided such that the same position is irradiated with microwaves. 
     In  FIG.  6   , an example is described in which one of the first frequency irradiating portions  204  is attached to the vessel  10   d  such that an area including the point A is irradiated with microwaves with the first frequency, one of the second frequency irradiating portions  205  is attached to the vessel  10   d  such that an area including the point B is irradiated with microwaves with the second frequency, and one of the first frequency irradiating portions  204  and one of the second frequency irradiating portions  205  are attached such that an area including the point C is irradiated with microwaves with the first frequency and the second frequency. For example, an example is shown in which the first frequency irradiating portions  204  are provided above the points A and C, and the second frequency irradiating portions  205  are provided above the point B and below the point C. There is no limitation on the positions at which the first frequency irradiating portions  204  and the second frequency irradiating portions  205  are provided, the number of irradiating portions provided, and the like. 
     As described in the foregoing embodiment, each of the first frequency irradiating portions  204  and the second frequency irradiating portions  205  includes, for example, a microwave oscillator  2001  and a transmitting portion  2002 . Note that the frequencies of microwaves that are produced by the microwave oscillators  2001  are different between the first frequency irradiating portions  204  and the second frequency irradiating portions  205 . The microwave oscillators  2001  that are included in the irradiating portions  203  are preferably semiconductor oscillators. The first frequency irradiating portions  204  and the second frequency irradiating portions  205  may have structures other than those described above. 
     The one or at least two sensors  40  are, for example, the same as the sensors in the foregoing embodiment. In this example, a case is described as an example in which three sensors  40  are provided at positions respectively near the point A, the point B, and the point C in the vessel  10   d , for example, near positions above the point A, the point B, and the point C in the vessel  10   d.    
     The conveying units  60  are the same as those in the foregoing embodiment, and thus a detailed description thereof has been omitted. 
     The control unit  52  controls the power of microwaves that are used for irradiation by the first frequency irradiating portions  204  and the second frequency irradiating portions  205  included in the microwave irradiating unit  22 . For example, the control unit  52  performs feedback control on the power of the first frequency irradiating portions  204  and the second frequency irradiating portions  205  that irradiate the point A, the point B, and the point C with microwaves, according to the information of the temperatures of the treatment target  2  acquired by the three sensors  40 . Note that the control does not have to be feedback control. If the microwave irradiating unit  22  includes multiple irradiating portions (not shown) that can control the phases of microwaves that are used for irradiation, the control unit  52  may control the frequency of microwaves that are used for irradiation by the irradiating portions respectively included in the microwave irradiating unit  22 . 
     Next, an operation the microwave treatment apparatus  1   b  of this embodiment will be described by way of a specific example. In this example, a case will be described as an example in which flame-resistance treatment on a PAN-based precursor fiber that is the treatment target  2  is performed using the microwave treatment apparatus  1   b . Hereinafter, for the sake of convenience of description, a description will be given using the microwave treatment apparatus  1   b  shown in  FIG.  6   . It is assumed that the microwaves that are used for irradiation by the first frequency irradiating portions  204  are microwaves with the first frequency at which microwaves absorbed by the heat generating member  30  are greater than microwaves transmitted through the heat generating member  30 , and the microwaves that are used for irradiation by the second frequency irradiating portions  205  are microwaves with the second frequency at which microwaves absorbed by the heat generating member  30  are less than microwaves transmitted through the heat generating member  30 . Also, it is assumed that the heat generating member  30  in this case has a thickness that allows the heat generating member to absorb more than half of the microwaves with the first frequency that are used for irradiation, preferably a large portion thereof, and to transmit more than half of the microwaves with the second frequency that are used for irradiation, preferably a large portion thereof, without absorbing the microwaves. 
     For example, in a state in which the treatment target  2  is conveyed by the conveying units  60 , microwaves  16  at the first frequency are always used for irradiation by the first frequency irradiating portions  204 , and microwaves  17  at the second frequency are always used for irradiation by the second frequency irradiating portions  205 . In this example, it is assumed that the power of the microwaves  16  that are used for irradiation by the first frequency irradiating portions  204  and the power of the microwaves  17  that are used for irradiation by the second frequency irradiating portions  205  are subjected to feedback control according to the information of temperature acquired by the sensors  40  provided respectively in the vicinity thereof. 
     At the point A, the microwaves  16  at the first frequency are used for irradiation by the first frequency irradiating portions  204 , and thus the first microwave irradiation is performed. Thus, microwaves are likely to be absorbed by the heat generating member  30 , and the treatment target  2  is not likely to be irradiated with the microwaves  16 , as a result of which, as shown in  FIG.  6 B , the heat generation at the heat generating member  30  is greater than the heat generation at the treatment target  2 . Accordingly, the treatment target  2  is heated from the outside by radiant heat from the heat generating member  30 . Although the amount of heat is smaller than that of the heat generating member  30 , the treatment target  2  is directly heated as well by part of the microwaves  16  that are used for irradiation. 
     At the point B, the microwaves  17  at the second frequency are used for irradiation by the second frequency irradiating portions  205 , and thus the second microwave irradiation is performed. Thus, microwaves are unlikely to be absorbed by the heat generating member  30 , and the treatment target  2  is irradiated with the microwaves  17  transmitted through the heat generating member  30 , as a result of which, as shown in  FIG.  6 C , the heat generation at the treatment target  2  is greater than the heat generation at the heat generating member  30 . Accordingly, the treatment target  2  is directly heated by the microwaves  17  that are used for irradiation. The heat generating member  30  is heated as well by part of the microwaves  17  that are used for irradiation, and thus the treatment target  2  is heated from the outside by radiant heat from the heat generating member  30 . 
     At the point C, the microwaves  16  at the first frequency are used for irradiation by the first frequency irradiating portions  204  to perform the first microwave irradiation and the microwaves  17  at the second frequency are used for irradiation by the second frequency irradiating portions  205 , and thus the second microwave irradiation is performed. Due to the microwaves  16  at the first frequency, the heat generation at the heat generating member  30  is greater than the heat generation at the treatment target  2 . Meanwhile, due to the microwaves  17  at the second frequency, the heat generation at the treatment target  2  by the microwaves  17  at the second frequency is greater than the heat generation at the heat generating member  30 . Accordingly, as shown in  FIG.  6 D , the treatment target  2  is heated from the outside by radiant heat from the heat generating member  30  by being irradiated with the microwaves  16  at the first frequency, and is directly heated by being irradiated with the microwaves  17  at the second frequency. 
     The power of the microwaves  16  and  17  with which the points A to C are irradiated is subjected to feedback control, for example, by the control unit  52  controlling the power of the first frequency irradiating portions  204  and the second frequency irradiating portions  205  that irradiate the respective points with microwaves, according to the information of the temperatures of the treatment target  2  acquired by the sensors  40  provided in portions respectively near the points. 
     It is possible to control the ratio between the amount of heat generated at the heat generating member  30  and the amount of heat generated at the treatment target  2  at the point C, by individually changing the power of the first frequency irradiating portions  204  and the second frequency irradiating portions  205  that perform irradiation the microwaves  16  and  17  with different frequencies to the point C. For example, it is possible to make the amount of heat generated at the heat generating member  30  higher than the amount of heat generated at the treatment target  2 , by increasing only the power of the microwaves  16  at the first frequency that are used for irradiation by the first frequency irradiating portions  204 , and it is possible to make the amount of heat generated at the treatment target  2  higher than the amount of heat generated at the heat generating member  30 , by increasing only the power of the microwaves  17  at the second frequency that are used for irradiation by the second frequency irradiating portions  205 . 
     For example, as described in the foregoing embodiment, at or near the position corresponding to the heat generation peak at the treatment target  2  on the movement path  2   a , if the microwave irradiation at the first frequency is performed in which the heat generation at the heat generating member  30  is greater than that at the treatment target  2  in a way similar to that at the point A described above, it is possible to properly treat the treatment target  2  while avoiding abrupt heating when the treatment target  2  reaches its heat generation peak. Also, at other positions on the movement path  2   a , for example, if microwaves with the first frequency, microwaves with the second frequency, or both microwaves with the first frequency and microwaves with the second frequency are used for irradiation as appropriate, it is possible to perform the first microwave irradiation and the second microwave irradiation in a proper combination to the treatment target  2  that moves, and to perform desired heating of the treatment target  2 . 
     The arrangement and the like of the first frequency irradiating portions  204  and the second frequency irradiating portions  205  are merely an example, and there is no limitation on the arrangement, the number, and the like of the first frequency irradiating portions  204  and the second frequency irradiating portions  205 . It is sufficient that the microwave treatment apparatus  1   b  includes at least one or more first frequency irradiating portions  204  and at least one or more second frequency irradiating portions  205 . For example, it is also possible that multiple first frequency irradiating portions  204  and multiple second frequency irradiating portions  205  are attached to the vessel  10 . 
     Furthermore, in the above-described specific example, it is also possible that the first frequency irradiating portions  204  and the second frequency irradiating portions  205  are provided as irradiating portions that irradiate multiple points with microwaves, and one or more of the multiple points are irradiated with microwaves with different frequencies in a way similar to that to the point C. In this case, it is also possible to irradiate one point with microwaves by only one of the first frequency irradiating portions  204  and the second frequency irradiating portions  205 , thereby performing irradiation with microwaves only with either one of the frequencies, or to switch the irradiating portion that irradiates one point with microwaves between the first frequency irradiating portions  204  and the second frequency irradiating portions  205 , thereby changing frequency of microwaves with which the one point is irradiated. 
     Furthermore, in the above-described specific example, it is also possible that, instead of providing the first frequency irradiating portions  204  and the second frequency irradiating portions  205 , multiple irradiating portions (not shown) that can change the frequency are provided, for example, along the movement path  2   a , and microwaves with a frequency suitable for each position are used for irradiation therefrom. For example, it is also possible that multiple irradiating portions that can change the frequency are provided above the points A to C as shown in  FIG.  6   , microwaves with the first frequency are used for irradiation by the irradiating portions above the point A and the point C, and microwaves with the second frequency are used for irradiation by the irradiating portion above the point B. In this manner, it is also possible that one irradiating portion that performs irradiation with microwaves with the first frequency and one irradiating portion that performs irradiation with microwaves with the second frequency are realized by one irradiating portion. 
     Furthermore, in this case, the frequency of microwaves that are used for irradiation by each irradiating portion may be changed as appropriate. For example, according to the material, the thickness, the movement speed, and the like of the treatment target  2 , the frequency of microwaves that are used for irradiation by the irradiating portion above the point B may be changed from the second frequency to the first frequency, and the frequency of microwaves that are used for irradiation by the irradiating portion above the point C may be changed from the first frequency to the second frequency. The frequency of microwaves that are used for irradiation by each irradiating portion may be changed according to the information of temperature and the like acquired by the sensors  40 . 
     Furthermore, it is also possible that multiple irradiating portions (not shown) that irradiate one or more points with microwaves are provided, each irradiating portion is an irradiating portion that can change the frequency of microwaves that are used for irradiation therefrom, the frequencies of microwaves of the multiple irradiating portions that irradiate each point with microwaves are different frequencies, and thus each point can be irradiated with microwaves with different frequencies. In this case, it is also possible that microwaves of the multiple irradiating portions that irradiate one point with microwaves are microwaves with the same frequency, or only one irradiating portion performs irradiation with microwaves, and thus a point that does not have to be irradiated with microwaves with different frequencies is irradiated with microwaves with only one frequency. 
     As described above, in this embodiment, it is possible to properly treat a treatment target using microwaves, by irradiating the internal portion of the vessel with microwaves with different frequencies, thereby performing the first microwave irradiation and the second microwave irradiation. For example, it is possible to perform proper heating, by controlling the combination and the ratio between the heating of a treatment target from the outside by a heat generating member caused to generate heat by microwaves, and the direct heating of a treatment target by causing the treatment target to generate heat with microwaves. 
     In Embodiment 3 above, it is also possible that the microwave irradiating unit  22  performs first microwave irradiation by which irradiation with microwaves is performed with a frequency at which a loss of microwaves to the heat generating member  30  is larger than a loss in the treatment target  2 , and second microwave irradiation by which irradiation with microwaves is performed with a frequency at which a loss in the heat generating member  30  is less than a loss in the treatment target  2 , instead of the above-described first microwave irradiation and second microwave irradiation. The loss of microwaves in this case may be considered as heat generation at the heat generating member  30  or the treatment target  2  with microwaves. The loss of microwaves can be expressed, for example, as a relative dielectric loss or the like. The relative dielectric loss is an imaginary part ε″ of the complex permittivity. Typically, heat generation through microwave irradiation increases in accordance with an increase in a relative dielectric loss, and heat generation through microwave irradiation decreases in accordance with a decrease in relative dielectric loss. 
     The frequency of microwaves that are used for irradiation in the first microwave irradiation in this manner may be considered as the above-described first frequency. The frequency of microwaves that are used for irradiation in the second microwave irradiation in this manner may be considered as the above-described second frequency. The relative dielectric loss in the heat generating member  30  in this case may be considered as the relative dielectric loss in the heating medium  301  of the heat generating member  30 . 
     In the description above, it is also possible that the vessel  10   d  includes multiple cavities, for example, one or at least two of either the first frequency irradiating portions  204  or the second frequency irradiating portions  205  are attached to each cavity, and thus the internal portion of each cavity is irradiated with microwaves with different frequencies. With this configuration, the treatment target  2  in each cavity can be irradiated with microwaves with different frequencies, and thus it is easy to control the power of microwaves with different frequencies that are used for irradiation, and the like. 
     Furthermore, in the foregoing embodiment, the case was described as an example in which the treatment target moves inside the vessel, but it is also possible that the treatment target  2  does not move inside the vessel  10   d , and the frequency of microwaves with which the internal portion of the vessel  10   d  is irradiated is changed over time, and thus the first microwave irradiation for heating the heat generating member  30  and the second microwave irradiation for heating the treatment target  2  can be performed in a switchable manner in a time unit, and the heating of the treatment target  2  from the heat generating member  30  and the direct heating of the treatment target  2  with microwaves can be performed in a switchable manner in a time unit. 
     In Embodiment 3 above, the case was described in which the microwave irradiating unit  22  performs irradiation with microwaves with two different frequencies, but it is also possible that the microwave irradiating unit  22  can perform irradiation with microwaves with three or more different frequencies. 
     For example, it is also possible that the microwave irradiating unit  22  includes one or more of each of three or more types of irradiating portions that perform irradiation with microwaves with different frequencies. It is also possible that the microwave irradiating unit  22  includes three or more irradiating portions that can change the frequency of microwaves that are used for irradiation, and the frequencies of microwaves that are used for irradiation by the irradiating portions such that three or more of them perform irradiation with microwaves with different frequencies. In the foregoing embodiment, it is also possible that portions of the multiple irradiating portions that can be shared are shared. 
     Furthermore, in Embodiment 2 above, it is also possible that two or more irradiating portions  203  that perform the first microwave irradiation perform irradiation with microwaves with the first frequency, and two or more irradiating portions  203  that perform the second microwave irradiation perform irradiation with microwaves with the second frequency as described in Embodiment 3 above. 
     Modified Example 1 
     In the microwave treatment apparatus  1   b  of Embodiment 3, it is also possible that one or at least two heat generating members  30  are provided inside the vessel  10   d  along part of the movement path  2   a  of the treatment target  2  as in Embodiment 1 described above, and the microwave irradiating unit  22  performs the first microwave irradiation by which one or more portions in which the heat generating members  30  are provided on the movement path  2   a  are irradiated with microwaves, thereby heating the heat generating members  30 , and the second microwave irradiation by which one or more portions in which the heat generating members  30  are not provided on the movement path  2   a  are irradiated with microwaves with a frequency that is different from that in the first microwave irradiation, thereby heating the treatment target. In other words, it is also possible that the microwave irradiating unit  22  irradiates one or more portions in which the heat generating members  30  are provided on the movement path  2   a  and one or more portions in which the heat generating members  30  are not provided on the movement path  2   a , with microwaves with different frequencies. 
     In this case, it is preferable that the frequency of microwaves for use in the first microwave irradiation is set to a frequency at which the relative dielectric loss in the heat generating members  30  is larger than the relative dielectric loss in the treatment target  2 . Also, it is preferable that the frequency of microwaves for use in the second microwave irradiation is set to a frequency at which the relative dielectric loss in the treatment target  2  is larger than the relative dielectric loss in the heat generating members  30 . Note that the frequency of microwaves for use in the second microwave irradiation may be a frequency at which the relative dielectric loss in the treatment target  2  is not larger than the relative dielectric loss in the heat generating members  30 . 
       FIG.  8 A  is a view illustrating an example of a modified example of the microwave treatment apparatus  1   b . This microwave treatment apparatus  1   b  is the microwave treatment apparatus  1   b  of Embodiment 3, wherein heat generating members  30   d  and  30   e  that are two heat generating members  30  as described in the modified example of Embodiment 2 are provided inside the vessel  10   d  at a predetermined interval along part of the movement path  2   a  of the treatment target  2 , and the microwave irradiating unit  22  includes two irradiating portions  206   a  and  206   b  that perform irradiation with microwaves with different frequencies from different positions, instead of the irradiating portion  204  and the irradiating portion  205 . In  FIG.  8 A , the vessel, the sensors, and the control unit, and the like are not shown. The solid arrows in the drawing schematically indicate microwaves that are used for irradiation by the irradiating portion  206   a  and the irradiating portion  206   b.    
     As shown in  FIG.  8 A , the irradiating portion  206   a  is attached at a position (e.g., the position on an unshown vessel that faces the side face of the heat generating member  30   d ) from which the heat generating member  30   d  can be irradiated with microwaves, and performs the first microwave irradiation by emitting microwaves with a frequency at which the relative dielectric loss in the heat generating member  30   d  is larger than the relative dielectric loss in the treatment target  2 . As shown in  FIG.  8 A , the irradiating portion  206   b  is attached at a position (e.g., the position on an unshown vessel that faces the area in which no heat generating members  30  is provided between the heat generating members  30   d  and  30   e ) from which the treatment target  2  that is located at the portion in which no heat generating member  30  is provided between the heat generating members  30   d  and  30   e  can be irradiated with microwaves, and performs the second microwave irradiation by emitting microwaves with a frequency that is different from that in the first microwave irradiation. The irradiating portions  206   a  and  206   b  may be irradiating portions as described above that are similar to the irradiating portion  204  and the irradiating portion  205  and the like that can perform irradiation with microwaves with the above-described frequencies. 
     In the microwave treatment apparatus  1   b  shown in  FIG.  8 A , when the irradiating portion  206   a  performs the first microwave irradiation, at a position  500   a  at which the microwaves used for irradiation are incident on the heat generating member  30   d , the relative dielectric loss in the heat generating member  30   d  is larger than the relative dielectric loss in the treatment target  2  due to the frequency for use in the first microwave irradiation, the heating efficiency is higher than that at the treatment target  2  that is located inside the heat generating member  30   d  under the position  500   a , and thus it is possible to efficiently heat the heat generating member  30   d , and to efficiently heat the treatment target  2  that is located inside, from the outside by the heated heat generating member  30   d . At the position inside the heat generating member  30   d  under the position  500   a , it is possible to suppress direct heating of the treatment target  2 . When the irradiating portion  206   b  performs the second microwave irradiation, at a position  500   b  at which the microwaves used for irradiation are incident on the treatment target  2  that is located at the portion in which no heat generating member is provided, it is possible to perform only direct heating of the treatment target  2  because no heat generating member  30  is provided. If the frequency of microwaves for use in the second microwave irradiation that are used for irradiation by the irradiating portion  206   b  is set to a frequency at which the relative dielectric loss in the treatment target  2  is large, it is possible to improve the heating efficiency of direct heating of the treatment target  2 . The position  500   a  and the position  500   b  shown in  FIG.  8 A  are positions for description, and do not strictly indicate the positions and the like that are actually irradiated with microwaves. The same applies to  FIGS.  8 B to  8 D  below. The same applies to a later-described position  500   c.    
     In this manner, in this modified example, it is possible to perform desired heating of the treatment target  2  at each of the positions at which the heat generating members  30  are provided and the positions at which the heat generating members  30  are not provided, by irradiating the heat generating members  30 , and the treatment target  2  that is located in the areas in which the heat generating members  30  are not provided, with microwaves different frequencies. In particular, it is possible to suppress heating of the treatment target  2  in the portions in which the heat generating members  30  are provided, by irradiating the heat generating members  30  with microwaves with a frequency at which the relative dielectric loss in the heat generating member  30   d  is larger than the relative dielectric loss in the treatment target  2 . 
     Modified Example 2 
     In the microwave treatment apparatus  1   b  described in Modified Example 1 above, it is also possible that the microwave irradiating unit  22  further performs, in addition to the above-described first microwave irradiation and second microwave irradiation, third microwave irradiation by which the portions in which the heat generating members  30  are provided are irradiated with microwaves with a frequency at which the relative dielectric loss in the partially provided heat generating members  30  is smaller than the relative dielectric loss in the treatment target  2 , thereby heating the treatment target in the portions in which the heat generating members  30  are provided. 
       FIGS.  8 B to  8 D  are schematic views showing the heat generating members  30   d  and  30   e  and the vicinity thereof, illustrating a modified example of the microwave treatment apparatus  1   b  that further performs the above-described third microwave irradiation, where the reference numerals that are the same as those in  FIG.  8 A  denote the same or corresponding constituent elements. In the drawings, a irradiating portion  206   c  performs the third microwave irradiation, by irradiating the portions in which the heat generating members  30  are provided, with microwaves with a frequency at which the relative dielectric loss in the heat generating members  30  is smaller than the relative dielectric loss in the treatment target  2 . The irradiating portion  206   c  may be an irradiating portion as described above that is similar to the irradiating portion  204  and the irradiating portion  205  and the like that can perform irradiation with microwaves with the above-described frequencies. The irradiating portion  206   c  is attached to a vessel (not shown). The solid arrows in the drawings schematically indicate microwaves that are used for irradiation by the irradiating portion  206   a  and the irradiating portion  206   b , and the dashed arrow schematically indicates microwaves transmitted through the heat generating member  30 . In the drawings, it is assumed that a later-described position  500   c  indicates a position inside the heat generating member  30   d.    
     It is assumed that, as shown in  FIG.  8 B , the irradiating portion  206   c  is attached at a position on a vessel (not shown) that faces the side face of the heat generating member  30   d  such that a position on the heat generating member  30   d  is irradiated with microwaves, the position being different from the position  500   a  at which microwaves emitted from the irradiating portion  206   a  are incident through the first microwave irradiation. In this example, a case will be described as an example in which the irradiating portions  206  are attached such that the position at which microwaves used for irradiation by the irradiating portion  206   c  are incident on the heat generating member  30   d  is closer to the heat generating member  30   e  than the position  500   a  is, but it is also possible that the irradiating portions  206  are attached such that the position at which microwaves used for irradiation by the irradiating portion  206   c  are incident on the heat generating member  30   d  is farther from the heat generating member  30   e  than the position  500   a  is. 
     In the microwave treatment apparatus  1   b  shown in  FIG.  8 B , when the irradiating portion  206   a  performs the first microwave irradiation as in the microwave treatment apparatus  1   b  in  FIG.  8 A , at the position  500   a  at which the microwaves used for irradiation are incident on the heat generating member  30   d , it is possible to efficiently heat the heat generating member  30   d , and to suppress direct heating of the treatment target  2  in a portion under the position  500   a . When the irradiating portion  206   b  performs the second microwave irradiation, at the position  500   b  at which the microwaves used for irradiation are incident on the treatment target  2  that is located in the area in which no heat generating member is provided, it is possible to perform only direct heating of the treatment target  2 . Furthermore, when the irradiating portion  206   c  performs the third microwave irradiation, the relative dielectric loss in the treatment target  2  is larger than the relative dielectric loss in the heat generating member  30   d  due to the frequency for use in the third microwave irradiation, and thus, at a position  500   c  at which microwaves emitted from the irradiating portion  206   c  are incident on the treatment target  2  that is located inside the heat generating member  30   d , the heating efficiency of the treatment target  2  is high, as a result of which it is possible to efficiently perform direct heating of the treatment target  2  that is located inside. Also, in a portion in which microwaves emitted from the irradiating portion  206   c  are incident on the heat generating member  30   d , the heating efficiency is low, and thus it is possible to suppress heating of the heat generating member  30   d  from the outside through microwave irradiation by the irradiating portion  206   c , and to suppress heating of the treatment target  2  from the outside by the heated heat generating member  30   d.    
     In this manner, in this modified example, it is possible to properly heat the treatment target  2 , by performing the first microwave irradiation, the second microwave irradiation, and the third microwave irradiation. 
     The microwave treatment apparatus  1   b  described with reference to  FIG.  8 B  may be configured such that irradiation with microwaves is performed such that the position  500   a  irradiated with microwaves by the first microwave irradiation and the position  500   c  irradiated with microwaves by the third microwave irradiation are the same position in the direction that is along the movement path  2   a  of the treatment target  2 . For example, as shown in  FIG.  8 C , the microwave treatment apparatus  1   b  described with reference to  FIG.  8 B  may be configured such that the position  500   a  and the position  500   c  are the same position in the direction that is along the movement path  2   a  of the treatment target  2 , by attaching the irradiating portion  206   a  and the irradiating portion  206   c  to the vessel (not shown) such that their positions from which microwaves are emitted face each other with the heat generating member  30   d  interposed therebetween, and such that the position irradiated with microwaves by the first microwave irradiation and the position irradiated with microwaves by the third microwave irradiation are the same position in the direction that is along the movement path  2   a . Note that the arrangement of the irradiating portion  206   a  and the irradiating portion  206   c  is not limited to that described above, as long as the first microwave irradiation and the third microwave irradiation can be performed such that the positions to which irradiation with microwaves is performed are the same position in the direction that is along the movement path  2   a  of the treatment target  2 . For example, it is also possible that the irradiating portion  206   a  and the irradiating portion  206   c  are attached to the vessel such that their positions from which microwaves are emitted are the same position in the direction that is along the movement path  2   a  of the treatment target  2 , and do not face each other with the heat generating member  30   d  interposed therebetween. In the description above, it is also possible that irradiation with microwaves is performed such that the position  500   a  irradiated with microwaves by the first microwave irradiation and the position  500   c  irradiated with microwaves by the third microwave irradiation are the same position also in the width direction of the vessel  10   d . The position  500   a  irradiated with microwaves by the first microwave irradiation may be considered as the position at which one heat generating member  30  is heated through the first microwave irradiation, and the position  500   c  irradiated with microwaves by the third microwave irradiation may be considered as the position at which the treatment target  2  that is located in the portion in which one heat generating member  30  is provided is heated through the third microwave irradiation. The same applies to the description below. 
     Furthermore, the microwave treatment apparatus  1   b  described with reference to  FIG.  8 B  may be configured such that the position  500   a  irradiated with microwaves by the first microwave irradiation and the position  500   c  irradiated with microwaves by the third microwave irradiation are provided in portions in which different heat generating members  30  are provided. For example, it is also possible that, as shown in  FIG.  8 D , the position  500   a  irradiated with microwaves by the first microwave irradiation is provided in the portion in which the heat generating member  30   d  is provided, and the position  500   c  irradiated with microwaves by the third microwave irradiation is provided in the portion in which the heat generating member  30   e  is provided. In this case, for example, it is sufficient to arrange the irradiating portion  206   a  at the position that faces the side face of the heat generating member  30   d  such that the position  500   a  irradiated with microwaves by the first microwave irradiation is provided in the portion in which the heat generating member  30   d  is provided, and to arrange the irradiating portion  206   c  at the position that faces the side face of the heat generating member  30   e  such that the position  500   c  irradiated with microwaves by the third microwave irradiation is provided in the portion in which the heat generating member  30   e  is provided. Note that the arrangement of the irradiating portion  206   a  and the irradiating portion  206   c  is not limited to that described above, as long as irradiation with microwaves can be performed such that the position  500   a  irradiated with microwaves by the first microwave irradiation and the position  500   c  irradiated with microwaves by the third microwave irradiation are provided in portions in which different heat generating members  30  are provided. 
     In the description above, the case was described as an example in which the number of heat generating members  30  is two, but it is sufficient that the number of heat generating members  30  is one or more, if the third microwave irradiation is not performed as shown in  FIG.  8 A , if the position irradiated with microwaves by the first microwave irradiation and the position irradiated with microwaves by the third microwave irradiation are provided in a portion in which the same heat generating member  30  is provided as shown in  FIGS.  8 B and  8 C , or if different heat generating members do not have to be irradiated with microwaves. The lengths, materials, and the like of at least some of the two or more heat generating members  30  may be the same or different from each other. 
     Furthermore, it is sufficient that the number of heat generating members  30  is two or more, if the position irradiated with microwaves by the first microwave irradiation and the position irradiated with microwaves by the third microwave irradiation are provided in portions in which different heat generating members  30  are provided as shown in  FIG.  8 C . 
     Furthermore, the heat generating member  30  irradiated with microwaves by the first microwave irradiation and the area in which no heat generating member is provided and irradiated with microwaves by the second microwave irradiation may be adjacent to each other as shown in  FIG.  8 B , or may not be adjacent to each other. 
     Furthermore, if the position irradiated with microwaves by the first microwave irradiation and the position irradiated with microwaves by the third microwave irradiation are provided in portions in which different heat generating members  30  are provided, the first microwave irradiation position and the third microwave irradiation position may be heat generating members  30  that are adjacent to each other between which only one area in which no heat generating member  30  is provided, or may be heat generating members  30  that are provided such that two or more areas in which no heat generating member  30  is provided are interposed therebetween. 
     Furthermore, there is no limitation on the number of irradiating portion  206   a  included in the microwave treatment apparatus  1   b , as long as it is one or more. The same applies to the irradiating portion  206   b  and the irradiating portion  206   c.    
     Furthermore, it is also possible that the microwave irradiating unit  21  performs irradiation with microwaves such that the positions irradiated with microwaves by the first microwave irradiation are set to different multiple positions in the microwave treatment apparatus  1   b . For example, the microwave irradiating unit  21  may include multiple irradiating portions  206   a  that perform the first microwave irradiation to different multiple positions. The same applies to the second and third microwave irradiation positions. 
     Furthermore, in the foregoing embodiments, the case was described as an example in which the microwave treatment apparatus performs flame-resistance treatment on a treatment target that is a PAN-based precursor fiber or the like, but the microwave treatment apparatus can be used in treatment on treatment targets other than the precursor fibers and in treatment other than the flame-resistance treatment, and, also in these cases, effects that are similar to those in the foregoing embodiment are achieved. For example, there is no limitation on the material and the like of the treatment target. For example, the treatment target may be a cotton string, a wool string, a cashmere string, a polymer string, a metal string, or the like. The polymer string is, for example, a nylon string, a fluorocarbon string, a polythene string, or the like. For example, the above-described microwave treatment apparatus may be used to dry a cotton string, a wool string, a cashmere string, or the like. For example, the microwave treatment apparatus in the foregoing embodiments may be used in treatment such as heating, firing, sintering, or the like of a polymer string, a metal string, or the like. The microwave treatment apparatus in the foregoing embodiments may be used in carbonization treatment on a precursor fiber that has undergone flame-resistance treatment, that is, treatment to produce a carbon fiber using a precursor fiber that has undergone flame-resistance treatment. In the microwave treatment apparatus in the foregoing embodiments, after flame-resistance treatment as described above is performed on a precursor fiber, carbonization treatment may be performed in the same vessel to produce a carbon fiber. The treatment target  2  is not limited to those in the form of a fiber, and examples of the form include other forms such as a rod form, a chain form, a sheet form, a film form, and a tube form. The treatment target  2  does not absolutely have to continuously extend or to be continuously linked in a predetermined direction, as long as the treatment target  2  can be located inside the heat generating member or the like or can move inside the heat generating member, and, for example, it may be solid materials that are not continuous and that are placed on a belt (not shown) made of a material with high microwave transmission and configured to move inside the vessel from the inlet side to the outlet side, or may be a fluid such as a liquid or a powder, a gel, or the like that is placed and moves inside a tube or a pipe made of a material such as glass with high microwave transmission and configured to extend inside the vessel from the inlet side to the outlet side. The number of sets of microwaves that are used for irradiation by a microwave irradiating unit in the microwave apparatus, the microwave irradiation position, the power of microwaves, the frequency of microwaves, and the like are set as appropriate according to the treatment target, the treatment that is performed on a treatment target, and the like. 
     When producing a carbon fiber using a precursor fiber that has undergone flame-resistance treatment in the microwave treatment apparatus, for example, it is preferable that the gas supply units  70  described above supplies gas such as nitrogen necessary to produce a carbon fiber. 
     Furthermore, in the foregoing embodiments, the example was described in which the winding portion  65  that takes up the treatment target that has undergone treatment is arranged on the downstream side of the microwave treatment apparatus, but it is also possible that the treatment target that has undergone flame-resistance treatment is supplied to another treatment apparatus (not shown) without being taken up. For example, a precursor fiber that has undergone flame-resistance treatment with the microwave treatment apparatus may be sent as is into an apparatus (not shown) that performs carbonization treatment on the precursor fiber that has undergone flame-resistance treatment, using the conveying units  60 . 
     The flame-resistance treatment on a precursor fiber of a carbon fiber described in the foregoing embodiments may be considered as a step of the method for producing a carbon fiber. That is to say, the method for producing a carbon fiber including the flame-resistance treatment includes a step of irradiating an internal portion of a vessel with microwaves, the vessel including, therein, a heat generating member that generates heat by absorbing microwaves, thereby heating a precursor fiber of a carbon fiber that is provided along the heat generating member, wherein, in the heating step, the first microwave irradiation by which a heat generating member is heated and the second microwave irradiation by which a precursor fiber is heated are performed. 
     In the method for producing a carbon fiber, it is preferable that, when a precursor fiber reaches a temperature corresponding to the heat generation peak during the second microwave irradiation, the second microwave irradiation is stopped and the first microwave irradiation is performed. When reaching a temperature corresponding to the heat generation peak is, for example, a period including a point in time when reaching a temperature corresponding to the heat generation peak, and preferably a period including a point in time when reaching a temperature corresponding to the heat generation peak, and points in time before and after that point. 
     The present invention is not limited to the embodiment set forth herein. Various modifications are possible within the scope of the present invention. 
     INDUSTRIAL APPLICABILITY 
     As described above, the microwave treatment apparatus and the like according to the present invention are suitable as an apparatus and the like for performing desired treatment on a treatment target by performing irradiation with microwaves, and are particularly useful as an apparatus and the like for performing heating.