Patent Publication Number: US-2013245398-A1

Title: Capsule-type medical device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional application of U.S. application Ser. No. 11/702,871 filed on Feb. 6, 2007, which is a continuation application of U.S. application Ser. No. 10/395,745 filed on Mar. 24, 2003 which claims benefit of Japanese Application No. 2002-84387 filed on Mar. 25, 2002, the entire contents of each of which are incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a capsule-type medical device which is passed through the body cavity and is capable of examination, therapy, and/or treatment. 
     2. Description of the Related Art 
     Capsule-type medical devices are known as medical devices which are swallowed by patients to pass through the body cavity tract, which can perform examination, therapy, and/or treatment. 
     Such capsule-type medical devices comprise treatment tools for performing such medical treatment, such as a medication-depositing unit for depositing medicine, treatment devices such as forceps or the like, treatment devices for performing incision or coagulation by ultrasonic or high-frequency means, and so forth, and are arranged to perform such medical treatment at an object portion in the body cavity tract. However, there are shortcomings within the capsule-type medical devices, such as requiring a long time to reach the object portion unless guided through the body cavity tract. 
     To deal with this problem, Japanese Patent Publication No. 3017770 discloses a capsule-type medical device comprising a magnet which is magnetically manipulated by a magnet outside of the body of the subject. With the medical device described in Japanese Patent Publication No. 3017770 (hereafter referred to simply as “No. 3017770”), an external uniform magnetic field uniaxially acts upon magnets provided on the outer perimeter of a capsule main body in the vertical direction, so that the capsule is guided through the body cavity tract without rotating, primarily. Also, an arrangement is also disclosed wherein an alternating magnetic field is applied externally, so as to rotate the main body. However, efficiently propelling rotational motion of the main unit is not easy. 
     Note that this No. 3017770 is equivalent to the Japanese Patent Application with Application No. H2-109696 (filed on Apr. 25, 1990) which is cited as proof of prior application in the later-described U.S. Pat. No. 5,681,260. 
     On the other hand, with the capsule-type medical device described in Japanese Unexamined Patent Application Publication No. 2001-179700 (hereafter referred to simply as “No. 2001-179700”), an external rotating magnetic field acts triaxially on a magnet provided within the capsule main unit in the vertical direction and horizontal direction, so as to gain propulsion by rotationally turning. 
     With the capsule-type medical device described in No. 2001-179700, a thrust generating unit which obtains propulsion by rotating is provided in the capsule main unit. However, with the capsule-type medical device described in No. 2001-179700, no consideration has been given to the internal structure of the capsule main unit with regard to rotations of the capsule main unit. 
     Accordingly, the capsule-type medical device described in No. 2001-179700 may make useless motions such as rotating eccentrically (zigzagging), and accordingly take time to reach the object position in the body cavity tract, rather than reaching the location smoothly. 
     Also, U.S. Pat. No. 5,353,807 discloses a configuration comprising a slender and flexible recovery member, a main unit disposed on the tip thereof for performing medical treatment, a coil provided on the circumference to the main unit for guiding with an eternal magnetic flux, and multiple propulsion plates provided on the recovering member, thereby enabling the direction of the main unit to be controlled by the magnetic polarity generated by the coil and the external magnetic flux, and further guiding the main unit through the body cavity by a propulsion plate provided on the recovering member. 
     This patent also discloses an arrangement of a main unit comprising an internal magnet and battery, with the capsule not being provided with the recovering member but rather guided by the external magnetic field. 
     However, with the arrangement described in this U.S. Patent, the direction of the magnetic polarity generated by the coil or the magnet is in the longitudinal direction of the main unit, so smooth propulsion by an external magnetic field is not easy. 
     Also, U.S. Pat. No. 5,681,260 also discloses a device wherein an endoscope insertion portion or the like is magnetically guided through the body cavity, besides the embodiment relating to  FIGS. 50 through 76B  corresponding to No. 3017770. 
     The arrangement described in this U.S. patent has a similar configuration as that in No. 3017770, and smooth propulsion of the endoscope insertion portion or the like is not easy. 
     Further, the above-described preceding examples do not disclose contents corresponding to the Claims of the Present Invention. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a capsule-type medical device with little useless motions such as eccentric rotations, and which can be smoothly and readily propelled through body cavities. 
     It is another object of the present invention to provide a capsule-type medical device which can be readily propelled through bending body cavities. 
     To achieve these objects, the capsule-type medical device according to the present embodiment comprises: a capsule main unit provided with functions for performing medical acts such as examination, therapy, and/or treatment; a magnet provided to the capsule main unit, for magnetically acting upon an external magnet outside of the subject; and a propulsion generating unit for converting rotational motion due to the magnet into propelling force; wherein the center of gravity of the capsule main unit generally matches the center axis of the capsule main unit in the longitudinal direction, thereby suppressing useless motions such as eccentric rotations, and enabling the capsule-type medical device to be smoothly propelled through the body cavity to the target position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1 through 14B  relate to a first embodiment of a present embodiment, wherein  FIG. 1  is an overall configuration diagram illustrating a medical system with the first embodiment of the present invention; 
         FIG. 2  is a block diagram illustrating the configuration of the electrical system according of the capsule-type medical device according to the first embodiment; 
         FIG. 3A  is a cross-sectional diagram illustrating the configuration of the capsule-type medical device; 
         FIG. 3B  is a frontal view illustrating the tip side of the arrangement shown in  FIG. 3A ; 
         FIG. 3C  is a rear side view illustrating the rear end view of the arrangement shown in  FIG. 3A ; 
         FIG. 3D  is a cross-sectional view illustrating the configuration of the capsule-type medical device with the placement position of the magnet changed; 
         FIG. 4A  is an external explanatory diagram of a capsule-type medical device for spreading a medicine; 
         FIG. 4B  is an external view of the tip side of the capsule-type medical device shown in  FIG. 4A ; 
         FIG. 5A  is an explanatory diagram illustrating a capsule-type medical device comprising a treatment tool storage unit and ultrasonic unit, wherein an elastic rubber cover having a spiral groove formed thereupon is detachably mounted to the capsule main unit; 
         FIG. 5B  is a perspective view illustrating a part of the elastic rubber cover shown in  FIG. 5A ; 
         FIG. 6A  is a cross-sectional diagram illustrating a capsule-type medical device wherein a spiral portion provided to the rear side with regard to the direction of progression is detachably provided, and an observation devices is provided on the rear side with regard to the direction of progression; 
         FIG. 6B  is a transverse cross-sectional diagram of the arrangement shown in  FIG. 6A ; 
         FIG. 7A  is a cross-sectional view illustrating a capsule-type medical device wherein multiple magnets are symmetrically disposed on the center axis of the capsule main unit in the longitudinal direction. 
         FIG. 7B  is a transverse cross-sectional diagram of the arrangement shown in  FIG. 7A ; 
         FIG. 8A  is a cross-sectional view illustrating a capsule-type medical device wherein a spiral portion is detachably provided to the side at the direction of progression, while an observation device is provided on the rear side with regard to the direction of progression; 
         FIG. 8B  is a cross-sectional diagram viewing the arrangement shown in  FIG. 8A  from the lower side of the drawing; 
         FIG. 9A  is an explanatory diagram illustrating a capsule-type medical device which is recovered by a recovery tool inserted through a treatment device insertion channel of an endoscope; 
         FIG. 9B  is a transverse cross-sectional view at the tip side of the arrangement shown in  FIG. 9A ; 
         FIGS. 10A through 10C  show a configuration wherein the capsule main unit can be divided into the two parts of a portion where an observation device is disposed, and a portion where a magnet and spiral portion are disposed, wherein  FIG. 10A  is an explanatory diagram illustrating a capsule-type medical device wherein the observation field of view of the observation device is directed backwards; 
         FIG. 10B  is an explanatory diagram illustrating a capsule-type medical device wherein the observation field of view of the observation device is directed diagonally backwards; 
         FIG. 10C  is an explanatory diagram illustrating a capsule-type medical device wherein the observation field of view of the observation device is directed toward the side; 
         FIG. 11A  is an explanatory diagram illustrating a capsule-type medical device wherein a portion to which a spiral portion is provided is formed at a flexible insertion portion; 
         FIG. 11B  is a transverse cross-sectional diagram of the arrangement shown in  FIG. 11A ; 
         FIG. 12A  is an explanatory diagram illustrating a capsule-type medical device provided with a ring-shaped magnet; 
         FIG. 12B  is a transverse cross-sectional diagram of the arrangement shown in  FIG. 12A ; 
         FIGS. 13A through 13C  illustrate a capsule-type medical device wherein a spiral portion is provided on the opposite side as to a flexible insertion portion on one end of the capsule main unit which is the progression direction thereof in the longitudinal direction, wherein  FIG. 13A  is an explanatory diagram illustrating a capsule-type medical device wherein the spiral portion is provided over almost the entire circumference of the rear side of the capsule main unit; 
         FIG. 13B  is an explanatory diagram illustrating a capsule-type medical device wherein the spiral portion is provided diagonally over half of the rear side of the capsule main unit so as to enable diagonally viewing in the backward direction; 
         FIG. 13C  is an explanatory diagram illustrating a capsule-type medical device wherein the spiral portion is provided over half of the rear side of the capsule main unit so as to enable viewing sideways; 
         FIG. 14A  is an explanatory diagram illustrating a capsule-type medical device wherein the flexible insertion portion is detachably mounted to the capsule main unit; 
         FIG. 14B  is an explanatory diagram illustrating that the flexible insertion portion is bendable in the direction generally orthogonal to the longitudinal direction; 
         FIGS. 15 through 21  relate to a second embodiment of the present invention, wherein  FIG. 15  is an explanatory diagram illustrating a capsule-type medical device according to the second embodiment of the present invention; 
         FIG. 16  is an explanatory diagram illustrating the operations of the capsule-type medical device shown in  FIG. 15  within the body cavity; 
         FIG. 17  is an explanatory diagram illustrating the relation between the length of the rigid portion of the capsule main unit and the length of the soft portion of the flexible insertion portion, with regard to the maximum diameter of the tubular body cavity organ; 
         FIG. 18  is an explanatory diagram of the operations of the capsule-type medical device shown in  FIG. 15  in bent or narrow portions or the like in tubular body cavity organs; 
         FIG. 19  is an external diagram illustrating a capsule-type medical device wherein the spiral portion is formed by adhesion and fixing of a wire-like material to the outer perimeter of the flexible insertion portion; 
         FIG. 20  is an explanatory diagram illustrating a capsule-type medical device wherein the flexible insertion portion is configured with multiple ball-shaped protrusions formed with ball-shaped magnets built therein, formed thereupon; 
         FIG. 21  is an explanatory diagram illustrating the operations of the capsule-type medical device shown in  FIG. 20  inside the body cavity; 
         FIGS. 22 and 23  relate to a third embodiment of the present invention, wherein  FIG. 22  is an explanatory diagram illustrating a capsule-type medical device according to the third embodiment of the present invention; and 
         FIG. 23  is an explanatory diagram illustrating a modification example of the capsule-type medical device shown in  FIG. 22 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following is a description of embodiments of the present invention, with reference to the drawings. 
     First Embodiment 
     A first embodiment of the present invention will be described with reference to  FIGS. 1 through 14B . The primary object of the present embodiment is to provide a device and method wherein a capsule-type medical device which performs medical actions can be rotated by external magnetism and thus be smoothly guided to a target portion or beside a target portion; more specifically, to provide a device and method wherein eccentric motion in rotation is suppressed so as to enable effective or smooth propulsion to beside the target portion. 
     As shown in  FIG. 1 , a capsule-type medical device  1  exchanges radio waves with a capsule control device (hereafter referred to simply as “control device”)  3  while passing through the body cavity tract of a patient  2 , thus configuring a medical system  4  enabling examination, therapy, and/or treatment, under control of this control device  3 . 
     The medical system  4  is for performing screening of the esophagus, duodenum, small intestine, large intestine, etc., by swallowing the capsule-type medical device  1  with water or the like in the same way that one would swallow medicine, following precleaning of the large intestine (lavage of the intestinal tract). In the event that the capsule-type medical device  1  passes through an area of interest rapidly, as with the duodenum for example, the medical system  4  takes images at a rate of 10 frames per second, and on the other hand, takes images at 2 frames per second for areas passed through slowly, such as the small intestine, for example. The images that are taken are subjected to necessary signal processing and digital compression processing and then transmitted to the control device  3 , and only information necessary is recorded as moving images so as to be used for diagnosis. 
     Also, the medical system  4  is configured comprising a magnetic guiding device  5  which magnetically guides the capsule-type medical device  1 . Note that  FIG. 1  only shows the magnetic guiding device  5  schematically. The magnetic guiding device  5  is configured so as to form a rotating magnetic field which magnetically acts upon a later-described magnet provided in a capsule main unit  1 A of the capsule-type medical device  1 . Also, the magnetic guiding device  5  is connected to the control device  3 , such that the control device  3  can control the direction of the generated rotating magnetic field. 
     The control device  3  comprises a personal computer main unit  11  having functions for controlling the capsule-type medical device  1  and the magnetic guiding device  5 , a keyboard  12  which is connected to the personal computer main unit  11  for inputting commands, data, etc., a monitor  13  which is connected to the personal computer main unit  11  for displaying images and the like, and an external antenna  14  which is connected to the personal computer main unit  11  for transmitting control signals for controlling the capsule-type medical device  1  and receiving signals from the capsule-type medical device  1 . 
     The control device  3  is arranged such that the control signals for controlling the capsule-type medical device  1  and the magnetic guiding device  5  are generated based on key input from the keyboard  12  or by a control program stored in a hard disk or the like within the personal computer main unit  11 . 
     The control signals for controlling the magnetic guiding device  5  are transmitted from the external computer main unit  11  to the magnetic guiding device  5  by a connecting cable not shown in the drawings. 
     The magnetic guiding device  5  generates the rotating magnetic field wherein the direction of the rotating magnetic field is controlled, based on the transmitted control signals. The capsule-type medical device  1  is configured such that the rotating magnetic field generated by the magnetic guiding device  5  magnetically acting upon the later-described magnet rotates the capsule main unit  1 A such that the direction of progression of the capsule main unit  1 A within the body cavity is set by a later-described propulsion generating unit, and also such that motive energy for propulsion of the capsule main unit  1 A is generated. 
     On the other hand, the control signals for controlling the capsule-type medical device  1  are modulated by carrier waves of a predetermined frequency at an oscillating circuit within the personal computer main unit  11 , and transmitted as radio waves from the external antenna  14 . 
     The capsule-type medical device  1  receives the radio waves with a later-described wireless antenna  21 , the control signals are demodulated, and the demodulated control signals are output to the component circuits and the like. 
     Also, the control device  3  receives signals including image information of video signals and the like transmitted from the wireless antenna  21  of the capsule-type medical device  1  with the external antenna  14 , and displays images and the like on the monitor  13 . 
     Next, a detailed configuration of the capsule-type medical device according to the present embodiment will be described with reference to  FIGS. 2 through 3C . Note that the present embodiment is a capsule-type medical device capable only of examination (observation). 
     The capsule-type medical device  1  is primarily configured of a wireless antenna  21  which exchanges radio waves with the control device  3 , a wireless transmission/reception circuit  22  which subjects the radio waves exchanged with the wireless antenna  21  to signal processing, an illumination device  23  of LEDs (Light-Emitting Diodes) or the like which emits illumination light for illuminating the body cavity, an observation device (imaging device)  24  for acquiring optical images of the body cavity illuminated with the illumination light from the illumination device  23  so as to take images, a digital signal processing circuit  25  for performing digital signal processing or the like with regard to the imaging signals obtained from the imaging device  24 , a battery unit  26  where a battery  26   a  of some sort is stored, and a switch  27  which turns electrical power supplied from the battery unit  26  off and on. 
     The wireless transmission/reception circuit  22  selectively extracts carrier waves of the radio waves received from the control device  3  using the wireless antenna  21 , and performs detection, demodulation of control signals, and output thereof to the component circuits, as well as modulating information signals such as video signals or the like from the component circuits with carrier waves of a predetermined frequency, and transmitting these from the wireless antenna  21  as radio waves. 
     The observation device  24  is configured of an object optical system  31  for acquiring optical images, an imaging sensor  32  such as a CMOS (Complementary Metal-Oxide Semiconductor) or the like for imaging the optical images acquired by the object optical system  31 , and an imaging driving circuit  33  for driving the imaging sensor  32 . 
     The digital signal processing circuit  25  is configured of a digital video signal processing circuit (hereafter referred to as “video signal processing circuit”)  34  which subjects the imaging signals taken by the imaging sensor  32  to signal processing and converts these into digital video signals, and a digital compression processing circuit (hereafter referred to as “compression processing circuit”)  35  which subjects the converted digital video signals to compression processing. 
     The battery unit  26  supplies electric power from the stored battery  26   a  to the illumination device  23 , the digital signal processing circuit  25 , and the wireless transmission/reception circuit  22  through the switch  27 . Note that the observation device  24  is supplied electric power from the battery  26   a  via the digital signal processing circuit  25 . 
     Also, the capsule-type medical device  1  has built in a permanent magnet (hereafter referred to simply as “magnet”)  36  upon which the rotating magnetic field, generated by the magnetic guiding device  5  as described above, acts. The magnet used there is a permanent magnet such as a neodymium magnet, samarium-cobalt magnet, ferrite magnet, iron-chromium-cobalt magnet, platinum magnet, Alnico (AlNiCo) magnet, and so forth. 
     Rare-earth magnets such as neodymium magnets and samarium-cobalt magnets have strong magnetism and are advantageous in reducing the size of the magnet built into the capsule main unit  1 A. On the other hand, ferrite magnet are advantageous in that the cost is low. Further, platinum magnets have excellent corrosion resistance, and are suitable for medical purposes. 
     Also, the magnet  36  built into the capsule main unit  1 A needs not be a permanent magnet, and rather may be formed of a coil instead. In this case, the capsule main unit  1 A may generate magnetism at the coil by current from an electric power source such as a built-in battery or the like, or the coil may be magnetized by electric power temporarily stored in an built-in capacitor or the like. 
     Further, instead of a built-in power source, the capsule main unit  1 A may have a coil built in which is used to generate electricity, which is stored in a capacitor and used to magnetize a separate coil. In this case, the limit on capacity of a built-in battery is done away with for the capsule main unit  1 A, thereby enabling operations over long periods of time. Also, the same coil may be used for the coil for generating electricity and the magnetizing coil. 
     As shown in  FIGS. 3A through 3C , the capsule-type medical device  1  has a cylindrical capsule main unit  1 A covered with a transparent main unit exterior member  41  in an airtight manner, with components built in such as the above-described illumination device  23  and observation device  24  being positioned within the cylindrical capsule main unit  1 A. More specifically, the object optical system  31  making up the observation device  24  is positioned at the center portion of the tip side of the cylindrical capsule main unit  1 A of the capsule-type medical device  1 , and the imaging sensor  32  is positioned at the image focus location of the object optical system  31 . 
     The imaging driving circuit  33  is formed so as to surround the imaging sensor  32 . The digital signal processing circuit  25  is positioned at the base side of the imaging driving circuit  33  and the imaging sensor  32 , with the wireless transmission/reception circuit  22  disposed at the base side of the digital signal processing circuit  25 . 
     Also, the illumination device  23  is formed so as to surround the object optical system  31 , thereby illuminating in front of the capsule main unit  1 A with illumination light through the transparent main unit exterior member  41 . As shown in  FIG. 3B , the illumination device  23  is configured of an array of four white LEDs, for example. 
     The battery unit  26  is provided on the rear side of the wireless transmission/reception circuit  22 , with three batteries  36   a  such as button batteries stored in the battery unit  26 . Upon the battery unit  26  being turned on by the switch  27  being operated externally, an operation which is not indicated in the drawings, electric power is supplied to the illumination device  23  and the like through the switch  27 . The magnet  36  is positioned behind the battery unit  26 , with the wireless antenna  21  positioned further behind. 
     The capsule-type medical device  1  has the above-described built-in components reinforced and held by a cylindrical member such as a metal ring reinforcing member not shown in the drawings, and placed in the main unit exterior member  41 . The capsule-type medical device  1  is formed to a size wherein the patient  2  can swallow the capsule main unit  1 A without much trouble. 
     Also, the capsule-type medical device  1  has the magnet  36  disposed therein such that the poles N and S are perpendicular to the center axis  38  in the longitudinal direction of the cylindrical shape of the capsule main unit  1 A, as shown in  FIG. 3A  (i.e., in  FIG. 3A , the center axis  38  is horizontal, and the direction of magnetic polarity is vertical, which is perpendicular thereto). 
     Thus, with the capsule-type medical device  1 , upon the rotating magnetic field generated by the magnetic guiding device  5  acting upon the magnet  36 , the capsule main unit  1 A rotates on the longitudinal center axis  38  due to the magnet  36  being acted upon. 
     Also, the capsule-type medical device  1  is provided with a propulsion generating unit on the outer perimeter of the capsule main unit  1 A, which is a spiral portion  37  made up of spiral grooves  37   a  through which fluids such as gas and liquids in the body cavity can flow through in either direction, and spiral ridges  37   b  where portions next to the spiral grooves  37   a  protrude in a spiraling manner. Note that the spiral ridges  37   b  are formed with curved faces so as to smoothly come into contact with the inner walls of the body cavity. 
     Providing such a spiral portion  37  allows the capsule-type medical device  1  to move forward or backwards according to rotations of the capsule main unit  1 A, since rotations are converted into propulsion force as the fluids such as gas and liquids in the body cavity pass through the spiral grooves  37   a  making up the spiral portion  37 . 
     Also, the capsule main unit  1 A can be propelled following the spirals upon rotation, by using the friction between the protrusions of the spiral ridges  37   b  making up the spiral portion  37  and the mucous membranes. 
     That is to say, in the event that the protrusions of the spiral ridges  37   b  come into contact with the inner walls, and the capsule main unit  1 A is rotated in that state, the capsule main unit  1 A rotates in a state wherein spinning free is restricted by the friction at the point of contact, so the rotations propel the capsule main unit  1 A in spiral fashion as to the inner walls. Reversing the direction of rotation allows the direction or progression of the capsule main unit  1 A to be reversed. 
     Let us say that the spiral protrusions formed for the spiral ridges  37   b  are cyclically formed with a pitch of p, for example. In a normal state of use wherein the spiral ridges  37   b  are in contact with the tubular inner walls, one rotation of the capsule main unit  1 A propels the capsule main unit  1 A by the pitch p. 
     Note that the capsule-type medical device  1  is capable of changing the direction in which it is traveling according to the direction of rotation in which the capsule main unit  1 A rotates so as to match the rotating plane of the magnet  36  and the rotating plane of the rotating magnetic field according to the rotation of the rotating magnetic field. 
     Generally, with such a capsule-type medical device  1 , the capsule main unit  1 A may make useless motions such as eccentric motion (zigzagging) unless the center of gravity is not generally upon the longitudinal center axis  38  of the capsule main unit  1 A. 
     With the present embodiment, the capsule-type medical device  1  is configured such that the batteries  27   a  such as button batteries or the like, which are the heaviest built-in components, are positioned on the center axis  38  close to the center in the longitudinal direction, and the center  36   a  of the direction of magnetism of the magnet  36  is positioned on the center axis  38  of the capsule main unit  1 A, so that the center of gravity G of the capsule main unit  1 A is generally on the center axis  38  of the capsule main unit  1 A, as shown in  FIG. 3A . 
     Also, the built-in components may be arranged so as to match the center of gravity G of the capsule main unit  1 A by changing the position of the magnet  36  shown in  FIG. 3A  such that the center  36   a  of the direction of magnetism of the magnet  36  is positioned on the center axis  38  of the capsule main unit  1 A, as with the capsule-type medical device  1  shown in  FIG. 3D . 
     Configuring the capsule-type medical device  1  thus enables smooth guiding to the target position through the tubular body cavity or lumen without useless motions such as eccentric movement (zigzagging) of the capsule main unit  1 A. 
     Next, the operations of the capsule-type medical device  1  according to the present invention will be described. 
     As shown in  FIG. 1 , in the event that there is the need to observe a body cavity tract such as the stomach  51  for example, of the patient  2 , for long periods of time, the operator has the patient swallow the capsule-type medical device  1 , and causes the device to pass through the stomach. Immediately prior to having the patient  2  swallow the capsule-type medical device  1 , the operator turns the switch  27  thereof on, so that electric power from the batteries  26   a  in the battery unit  26  is supplied to the illumination device  23 , the observation device  24 , the digital signal processing circuit  25 , and the wireless transmission/reception circuit  22 . 
     At the same time, the operator activates (turns on) the magnetic guiding device  5 , and magnetically controls the capsule-type medical device  1  with the rotating magnetic field generated by the magnetic guiding device  5  so that the capsule-type medical device  1  reaches the target portion. 
     As described above, with the capsule-type medical device  1 , upon the rotating magnetic field generated by the magnetic guiding device  5  acting upon the magnet  36 , the capsule main unit  1 A is rotated by the force which the magnet  36  receives. 
     Then, the rotational force of the capsule main unit  1 A is converted into propulsion and the capsule-type medical device  1  proceeds forwards or retreats backwards, due to at least one of: fluids such as gas and liquids in the body cavity passing through the spiral grooves  37   a ; and the spiral ridges  37   b  smoothly coming into contact with the inner walls of the body cavity. Further, in the event that the capsule main unit  1 A comes into contact with the inner walls of the body cavity, the capsule main unit  1 A is held by friction between the mucous membranes on the inner walls of the body cavity and the spiral ridges  37   b , so rotations in this state are converted into greater propulsion force for proceeding forwards or retreating backwards. The capsule-type medical device  1  is capable of changing the direction in which it is traveling by the capsule main unit  1 A rotating with the rotating plane of the magnet  36  matching the rotating plane of the rotating magnetic field, according to the rotation of the rotating magnetic field. 
     Moreover, the capsule-type medical device  1  is capable of smoothly moving through the lumen to the target position without the capsule main unit  1 A making useless motions such as eccentric movement. 
     The capsule-type medical device  1  passes through the oral cavity  52  and the esophagus  53 , and reaches the stomach  51 . Now, the major axial diameter of the esophagus  53  is 16 mm and the minor axial diameter thereof is 14 mm, for example, so the capsule-type medical device  1  can easily pass through if formed with a generally circular cross-section 14 mm or less in outer diameter. 
     In the event that there is the need to observe the inside of the stomach  51 , the operator performs input corresponding to a command for staring observation, from a keyboard  12  for example of the control device  3 . Control signals from this key input are emitted as radio waves from the external antenna  14  of the control device  3 , and transmitted to the capsule-type medical device  1 . 
     The capsule-type medical device  1  detects operation-start signals from the signals received with the wireless antenna  21 , and drives the wireless transmission/reception circuit  22 , illumination device  23 , observation device  24 , and digital signal processing circuit  25 . 
     The illumination device  23  emits illumination light in the direction of the field of view of the observation device  24 , the optical image of the range of the field of view illuminated is imaged on the imaging sensor  32  of the observation device  24 , subjected to photo-electric conversion, and an imaging signal is output. This imaging signal is converted into digital video signals at the video signal processing circuit  34  of the digital signal processing circuit  25 , subjected to compression processing at the digital compression processing circuit  35  and modulated at the wireless transmission/reception circuit  22 , and emitted from the wireless antenna  21  as radio waves. 
     The radio waves are received with the external antenna  14  of the control device  3 , demodulated with the reception circuit within the personal computer main unit  11 , converted into digital signals with an A/D converter within the personal computer main unit  11 , and stored in memory, while also read out at a predetermined speed with an optical image taken with the imaging sensor  32  being displayed in color on the monitor  13 . The operator can observe the inside of the stomach  51  of the patient  2  by observing this image. The operator can further readily control how the external magnetic field is applied so that the entire stomach region can be observed, using operating means such as a joystick provided outside the body while observing the observation image. The optical image can also be recorded in an unshown image recording device. 
     Following observation of the stomach  51 , the capsule-type medical device  1  is magnetically guided by the rotating magnetic field formed by the magnetic guiding device  5  as described above, so as to pass from the stomach  51  through the duodenum  54 , the small intestine and large intestine which are not shown, and to be extracted from the anus. During this time, the capsule-type medical device  1  can observe the interior of the entire digestive tract. 
     Due to the configuration of the present embodiment, the capsule-type medical device  1  can suppress useless motions of the capsule main unit  1 A such as eccentric movement (zigzagging), enabling effective and smooth propulsion through the lumen to beside the target portion. 
     Also, no useless motions means that the magnetic guidance of the capsule-type medical device  1  is more effective, thus yielding the great advantage that one or both of the magnet  36  within the capsule and the external magnet or electromagnet can be reduced in size. 
     Also, the medical acts can be completed in a short time by propelling the capsule-type medical device  1  smoothly and efficiently. 
     Also, the capsule-type medical device may be configured for spreading medicine, as shown in  FIGS. 4A and 4B . That is to say, the capsule-type medical device  60  is configured having a medicine spreading opening  61   a  provided at the tip side so as to enable spreading of medicine stored in a medicine storing unit  61  within the capsule main unit  60 A. 
     Further, the capsule-type medical device  60  is configured to take body fluid samples. That is, the capsule-type medical device  60  is configured having a body fluid injecting opening  62   a  on the rear end so as to take samples of body fluid into a body fluid storing unit  62  within the capsule main unit  60 A. Opening and closing of the openings  61   a  and  62   a  is performed by communication control from the control device  3 . Thus, the capsule-type medical device  60  is capable of discharging and spreading medicine stored in the medicine storing unit  61  from the medicine spreading opening  61   a  to a target portions, and also is capable of taking samples of body fluid from the fluid injecting opening  62   a  into the body fluid storing unit  62 . 
     Also, it is needless to say that the medicine storing unit  61  may store a hemostatic agent for stopping bleeding, a ferrofluid or fluorescent agent which is safe to use with human bodies to externally determine hemorrhaging portions, and so forth, besides storing medicine. 
     Also, the capsule-type medical device  60  may be arranged to mix medicine stored in the medicine storing unit  61  with the body fluid taken in from the fluid injecting opening  62   a , and ejecting and spreading this mixture from the medicine spreading opening  61   a.    
     Note that this capsule-type medical device  60  has a spiral portion  37  formed on the outer perimeter of the capsule main unit, in the same way as with the capsule-type medical device  1  shown in  FIG. 3A . Also, the capsule-type medical device  60  has the center of gravity thereof generally upon the longitudinal center axis  38 . 
     Also, the capsule-type medical device  60  may be configured such that an elastic rubber cover having a spiral groove formed thereupon is detachably mounted to the capsule main unit as an exterior member, as shown in  FIGS. 5A and 5B . That is to say, as shown in  FIG. 5A , the capsule-type medical device  70  is configured such that an elastic rubber cover  71  having spiral grooves  69   a  (see  FIG. 5B ) formed thereupon can be detachably mounted to the capsule main unit  70 A. Thus, the capsule-type medical device  70  enables fluids such as gas and liquids in the body cavity to pass through the spiral grooves  69   a  of the elastic rubber cover  71  to the tip and rear sides thereof. 
     Also, the thick portions of the elastic rubber cover  71  having a shape like a belt wound thereupon forms the spiral ridges  69   b , thus forming the spiral portion  69 . 
     The capsule-type medical device  70  has a treatment tool storing portion  72  capable of therapy or treatment within the capsule main unit  70 A, and has a treatment tool opening  72   a  formed on the tip thereof. This treatment tool opening  72   a  is plugged with a soluble film such as gelatin which is digested by stomach fluid or a fatty acid which is digested by intestinal fluid, for example. The capsule-type medical device  70  is arranged to open the treatment tool opening  72   a  when reaching near the target portion. 
     The treatment tool  73  stored in the treatment tool storing portion  72  is capable of extending the tip thereof from the treatment tool opening  72   a  and retracting therein, and can perform therapy or treatment on the target portion of the body cavity tract. The treatment tool  73  is operated and controlled by communication control from the control device  3 . Specific operations of the treatment tool  73  may be carried out by operating means such as an unshown joystick or mouse or the like connected to the personal computer main unit  11 . 
     Note that in  FIG. 5A , the treatment tool  73  shown is an injection needle capable of injecting a hemostatic agent. With the capsule-type medical device  70  in this case, upon confirmation of a hemorrhaging portion with an unshown blood sensor or the observation device  24 , operations of the treatment tool  73  such as the hemostatic agent injection needle stored in the capsule main unit  70 A are instructed by communication control from the control device  3 , and a hemostatic agent such as ethanol or a powder medicine is spread onto the hemorrhaging portion, thereby stopping the bleeding. 
     Furthermore, the capsule-type medical device  70  comprises an ultrasonic unit  74  capable of examinations in the capsule main unit. The ultrasonic unit  74  is configured of an unshown ultrasonic probe for transmitting and receiving ultrasonic waves and an ultrasonic control circuit for controlling and driving the ultrasonic probe. 
     The capsule-type medical device  70  has the ultrasonic probe disposed in a watertight manner such that an unshown acoustic lens unit is positioned on the outer face of the rear end of the capsule main unit  70 A, such that a 360° ultrasonic tomographic image, for example, is obtained at the rear end side. 
     Then, with the capsule-type medical device  70 , the ultrasonic tomographic image data obtained is modulated at the wireless transmission/reception circuit  22  in the same manner as with the above-described observation image, and is emitted as radio waves from the wireless antenna  21 . Thus, the capsule-type medical device  70  is capable of diagnosing whether or not there are abnormalities in the depth-wise direction of deep portions in the body cavity wall, such as in the small intestine  55  or the like. In the event that the capsule-type medical device  70  is configured to have the observation device  24  as well, both the surface and deep portions of the body cavity can be diagnosed at once. 
     Also, the capsule-type medical device  70  is configured with the capsule main unit  70 A having connected thereto a string  75  formed of soft plastic or the like, having sufficient softness, diameter, and strength, to allow the capsule-type medical device  70  to be extracted from the stomach or small intestine through the mouth, or the large intestine from the anus, following inspection, without damaging the mucous membranes in the body cavity. The string  75  is formed in a soft fashion not to impede the rotational progress of the capsule main unit  70 A. The string  75  is used by fixing the base end outside of the body. Also, the center of gravity of the capsule-type medical device  70  generally is upon the center axis  38  in the longitudinal direction of the capsule main unit  70 A, as with in  FIG. 3A  and others. 
     The capsule-type medical device may be configured with the spiral portion  37  and the observation device  24  provided at the rear side of the capsule main unit in the direction of procession. 
     That is to say, the capsule-type medical device  80  shown in  FIGS. 6A and 6B  comprises an exterior member  80 B having a spiral portion  37  detachably formed on the rear side of the capsule main unit  80 A in the direction of progression thereof (toward the left in  FIG. 6A , in this case), as well as the observation device  24  along with the illumination device  23  in the backwards direction as to the direction of progression of the capsule main unit  80 A. 
     Also, the capsule-type medical device  81  shown in  FIGS. 7A and 7B  comprises multiple magnets  36 , and the magnets may be placed symmetrically across the longitudinal center axis  38  of the capsule main unit  81 A. As with the capsule-type medical device  80 , this capsule-type medical device  81  may be formed such that the exterior member  81 B provided with the spiral portion  37  to the capsule main unit  81 A is detachable. 
     Also, as shown in  FIGS. 8A and 8B , the capsule-type medical device may be formed such that the exterior member  83 B provided with the spiral portion  37  to the capsule main unit  83 A in the direction of progression thereof is detachable. Further, the observation device  24  may be provided along with the illumination device  23  in the backwards direction as to the direction of progression of the capsule main unit  83 A. 
     Now, reference numeral  27 B denotes a switch for tuning on and off electric power supplied from the batteries  26   a  in the battery unit  26 . 
     The capsule-type medical device  83  shown in  FIG. 8B  has the magnet  36  provided parallel to the longitudinal center axis  38  of the capsule main unit  83 A. The capsule-type medical device  83  comprises the digital signal processing circuit  25  and the wireless transmission/reception circuit  22  below the magnet  36 . 
     Also, the capsule-type medical device  83  is arranged so as to be recovered by a capsule recovery tool  86  inserted into a treatment tool insertion channel  85  of an endoscope  84 , as shown in  FIGS. 9A and 9B . 
     The endoscope  84  is arranged so that the capsule recovery tool  86  can be inserted through the treatment tool insertion channel  85 . Reference numeral  87  denotes an observation device provided to a distal end  84   a  of the insertion portion of the endoscope  84 . This observation device  87  is configured of an object optical system  87   a  and an imaging unit  87   b  comprising an imaging device provided at the imaging position of the object optical system  87   a.    
     The capsule recovery tool  86  is formed as a flexible rod, with a magnet  88  for recovering the capsule-type medical device  83  provided at the tip thereof. The capsule recovery tool  86  also has a recessed portion  89  formed such that the spiral portion  37  of the capsule main unit  83 A does not get in the way after the capsule-type medical device  83  is captured by the magnet  88 . 
     Also, an arrangement may be made wherein, as with the capsule-type medical device  90  shown in  FIG. 10A , the capsule main unit  90 A can be divided into the two portions of the portion where the observation device  24  is disposed, and the portion where the magnet  36  and the spiral portion  37  are provided. Thus, various combinations can be made for the capsule-type medical device  90  according to the use; an arrangement wherein the field of view of the observation device  24  is backwards as shown in  FIG. 10A , an arrangement wherein the field of view of the observation device  24  is diagonally backwards as shown in  FIG. 10B , and an arrangement wherein the field of view of the observation device  24  is sideways as shown in  FIG. 10C . 
     Also, the capsule-type medical device may be arranged such that a portion having the spiral portion  37  is formed of a flexible member such as elastic rubber or the like, as shown in  FIG. 11A , so as to form a flexible insertion portion to be inserted into the body cavity. 
     That is, with the capsule-type medical device  100  as shown in  FIG. 11A , the portion provided with the spiral portion  37  may be formed as a flexible insertion portion (a flexible soft portion)  101  formed of a long and small-diameter flexible member, provided at one end of the rigid capsule main unit  100 A, with two magnets  36   a  and  36   b  symmetrically disposed across the longitudinal center axis  38 . 
     With this capsule-type medical device  100 , the flexible insertion portion  101  has the same outer diameter as the outer diameter of one end of the generally-cylindrical capsule main unit  100 A to which it is fastened by screwing, and the tip (end) side of the flexible insertion portion  101  is narrower than this outer diameter. 
     In this case, as shown in  FIG. 11B , the capsule-type medical device  100  has the illumination device  23  thereof configured of multiple LEDs disposed in a ring-like shape around the observation device  24 . 
     Also, an arrangement may be made with a ring-shaped magnet  36 , as with the capsule-type medical device  100 ′ having the flexible insertion portion  101  as shown in  FIGS. 12A and 12B . With this capsule-type medical device  100 ′, the base end of the flexible insertion portion  101  is connected to the rigid capsule main unit  100 A by fitting or pressing. 
     Also, instead of providing the spiral portion  37  on the flexible insertion portion  101 , an arrangement may be made wherein the spiral portion  37  is provided on the rigid portion toward the rear on the side opposite to the flexible insertion portion  101  to which the flexible insertion portion  101  is connected (in the event that the flexible insertion portion  101  is at the front in the direction of advancing), as with the flexible insertion portion  101  as with the capsule-type medical device  110  shown in  FIGS. 13A through 13C . In  FIGS. 13A through 13C , the direction of advancing to the left, and the right side is the rear. The capsule-type medical device is swallowed, or inserted from the anus into the large intestine, so as to head in the direction of advancing. 
     In this case, various combinations can be made for the capsule-type medical device  110  according to the use; an arrangement wherein the field of view of the observation device  24  is backwards as shown in  FIG. 13A , an arrangement wherein the field of view of the observation device  24  is diagonally backwards as shown in  FIG. 13B , and an arrangement wherein the field of view of the observation device  24  is sideways as shown in  FIG. 13C . That is to say, the flexible insertion portion  101  and the rigid capsule main unit  110 A are separable. 
     With the capsule-type medical device  110  shown in  FIG. 13A , the spiral portion  37  is provided over almost the entire perimeter of the rear side of the capsule main unit  110 A. Also, with the capsule-type medical device  110  shown in  FIG. 13B , the spiral portion  37  is provided over half of the rear side of the capsule main unit  110 A in a diagonal manner, so as to allow observation in the diagonally backwards direction. Also, with the capsule-type medical device  110  shown in  FIG. 13C , the spiral portion  37  is provided over half of the rear side of the capsule main unit  110 A, so as to allow sideways observation. 
     Also, the capsule-type medical device may have a configuration wherein the flexible insertion portion is detachably mountable to the capsule main unit as shown in  FIG. 14A . That is to say, with the capsule-type medical device  120  shown in  FIG. 14A , the flexible insertion portion  121  is detachably mountable to the capsule main unit  120 A. 
     The flexible insertion portion  121  is soft, and thus easily bendable as shown in  FIG. 14B . The flexible insertion portion  121  has a structure which is not readily stretched or compressed in the longitudinal direction, but readily bends in the direction generally orthogonal to the longitudinal direction. 
     Note that though the present embodiment has a wireless antenna  21  for performing transmission and reception with the control device  3 , thus configuring a capsule-type medical device capable of examination, therapy, and/or treatment by passing through the body cavity under the control of the control device  3 , the present invention is by no means restricted to this arrangement, and rather may be formed as a capsule-type medical device which is not provided with a wireless antenna  21  and wherein information (data) such as optical images are extracted following passing through the body cavity tract and being recovered outside of the body. 
     Second Embodiment 
     A second embodiment of the present invention will be described with reference to  FIGS. 15 through 21 . The present embodiment has been made to serve the same purpose as that of the first embodiment. The present embodiment also aims to pass through bent body cavity portions more smoothly. 
     The second embodiment comprises a flexible insertion portion (flexible soft portion), detachably mounted to a rigid capsule main unit. Other configurations are approximately the same as the first embodiment, so the same components will be denoted with the same reference numerals, and detailed description thereof will be omitted. 
     With the capsule-type medical device  150  according to the second embodiment as shown in  FIG. 15 , the bendable flexible insertion portion  151  is formed so as to be even longer and smaller in diameter than the flexible insertion portion  101  shown in  FIG. 11A , for example, and is detachably mounted to the rigid capsule main unit  150 A. 
     The flexible insertion portion  151  formed of elastic rubber or the like has the magnet  36  built in so as to be positioned on the longitudinal center axis  38 , and has on the base side thereof a mounting portion  151   a  so as to be mounted onto the capsule main unit  150 A. The flexible insertion portion  151  is mounted onto the capsule main unit  150 A, thus configuring the capsule-type medical device  150 . 
     In this case, the diameter Da of a recessed portion provided on the mounting portion  151   a  at the base side of the flexible insertion portion  151  is smaller than the diameter Db of the capsule main unit  150 A, so that this recessed portion can be elastically attached to the capsule main unit  150 A. 
     Also, the capsule-type medical device  150  is configured with the center of gravity G thereof generally matching the longitudinal center axis  38  of the capsule main unit  150 A, as with the first embodiment (see  FIG. 16 ). 
     Also, as with the case of the flexible insertion portion  101 , the flexible insertion portion  151  is configured so as to be bendable in the direction orthogonal to the longitudinal direction, with the side portion thereof being formed smaller in diameter than the outer diameter of the capsule main unit  150 A, so as to have functions of bending following the bending body cavity tract such that the capsule main unit  150 A at the rear end can smoothly proceed, as specifically indicated in  FIG. 18 . 
     Accordingly, the capsule-type medical device  150  moves through the body cavity with the flexible insertion portion  151  exploring the way to proceed, as shown in  FIG. 16 . 
     Now, the capsule-type medical device  150  may be configured so that, with regard to the maximum diameter L of a lumen organ such as the large intestine or the like, the relation between the rigid length L 1  of the rigid capsule main unit  150 A and the soft length L 2  of the soft flexible insertion portion  151  is in the range of L 1 &lt;L&lt;L 1 +L 2  as shown in  FIG. 17 . 
     In this case, the capsule-type medical device  150  is longer than the maximum diameter L of the lumen organ and moreover the length of the rigid portion is short, so the direction thereof does not change in the lumen, and further, rotations from the magnet  36  are converted directly into propulsion, so the rotational force can be efficiently converted into propulsion, and smoothly move through the lumen. 
     Also, the capsule-type medical device  150  rotates due to the magnet  36  at bent and narrow portions in the lumen such as the small intestine and large intestine as shown in  FIG. 18 , with the flexible insertion portion  151  finding its way ahead, and the capsule main unit  150 A following the flexible insertion portion  151  can readily pass through, as well. 
     Accordingly, with the present embodiment, eccentric movement can be suppressed, and the capsule-type medical device  150  can be smoothly propelled to the target portion, as with the first embodiment. In this case, the flexible insertion portion  151  is formed even longer and smaller in diameter, so eccentric movement can be suppressed even further. 
     With the present embodiment, the flexible insertion portion  151  at the tip bends following the shape of bent tract in the lumen, and thus acts to allow the trailing capsule main unit  150 A to change direction so as to smoothly pass. The capsule-type medical device  150  thus smoothly passes through bent lumen portions as well, thereby reducing the time for medical examination and/or treatment. 
     Also, an arrangement may be made wherein a wire-like member  162  is fixed by adhesions to the outer perimeter of the flexible insertion portion  161  to form the spiral portion  37 , as with the capsule-type medical device  160  shown in  FIG. 19 . With such an arrangement for the capsule-type medical device  160 , the spiral portion  37  can be readily provided to the flexible insertion portion  161 . The wire-like member  162  may be formed of an elastic member such as rubber, shaped into a wire-like form. 
     Also, an arrangement may be made for the capsule-type medical device  170  wherein multiple ball-shaped magnets  172   a  are built into the flexible insertion portion  171  so as to form multiple ball-shaped protrusions  172 , as shown in  FIG. 20 . The flexible insertion portion  171  is soft, so the capsule-type medical device  170  can go to the depths of bent portions in the tubular organs such as the small intestine or large intestine, while rotating, as indicated in  FIG. 21 . 
     Third Embodiment 
     A third embodiment of the present invention will be described with reference to  FIGS. 22 and 23 . The primary objects of the present embodiment are approximately the same as those of the first and second embodiments. Also, the present embodiment also aims to enable medical examination and/or treatment to be performed even more efficiently. 
     With the third embodiment, two capsule main units are provided, a leading-side rigid portion and a trailing-side rigid portion, with the two rigid portions being connected with a string-like material covered with a soft elastic materials such as urethane or silicon rubber or the like which smoothly changes external form as shown in the drawings, for example. Other configurations are approximately the same as the first embodiment, so the same components will be denoted with the same reference numerals, and detailed description thereof will be omitted. 
     With the capsule-type medical device  200  according to the third embodiment, two capsule main units  200 A are provided, a leading-side rigid portion  201  and a trailing-side rigid portion  202 , with the two rigid portions  201  and  202  being connected with a string-like member  203  as shown in  FIG. 22 . Also, the capsule-type medical device  200  is configured with the center of gravity G thereof generally matching the longitudinal center axis  38  of the capsule main unit  200 A, as with the first embodiment. 
     Also, the capsule-type medical device  200  comprises the spiral portions  37  on both the leading-side rigid portion  201  and the trailing-side rigid portion  202 . Further, the observation device  24  is configured so as to have a field of view looking diagonally forwards at the tip of the trailing-side rigid portion  202 . 
     According to such a configuration, the capsule-type medical device  200  can obtain a good observation field of view even if in close contact with the lumen. 
     That is to say, the capsule-type medical device  200  proceeds while rotating, so the inner walls can be efficiently observed, and medical examination and/or treatment can be performed efficiently. 
     Also, with the capsule-type medical device  200 , a portion of the protrusions formed on the leading-side rigid portion  201  also come into the field of view of the observation device  24 , so a mark is made in this field of view to indicate the position (polarity) of the magnet  36 . 
     Also, an arrangement may be made for the capsule-type medical device  210  wherein magnets  36 , observation devices  24 , and illumination devices  23 , are provided to both the leading-side rigid portion  201  and trailing-side rigid portion  202  provided with the spiral portions  37 . In this case, propulsion can be generated for the capsule-type medical device  210  as long as one of the spiral portions  37  comes into contact with the inner walls of the lumen or with luminal fluids, regardless of whether the other spiral portion  37  is in contact with something. 
     This means that the capsule-type medical device  210  can be propelled efficiently, and medical examination and/or treatment can be performed efficiently. Also, providing observation means on both sides allows medical examination and/or treatment (image-taking, in this case) to be performed even in the event that the image from one is insufficient, by compensating with the image from the other. In order to expand this function, an arrangement may be made wherein the observation and illumination range of the observation devices  24  and illumination devices  23  of the trailing-side rigid portion  202  is changed as to the observation and illumination range of the observation devices  24  and illumination devices  23  of the leading-side rigid portion  201 , for example, widening the range as indicated by the dotted lines (only the range of observation is indicated, for sake of simplicity). 
     In this case, two types of imaged pictures with different observation ranges are obtained, so medical examination and/or treatment can be performed more efficiently. 
     According to the present invention described above, a capsule-type medical device which can smoothly reach a target position through the lumen tract without useless motions such as eccentric movement can be realized. Further, according to the present invention, magnetic guiding efficiency is improved by reducing the unnecessary movement, so a capsule-type medical device wherein one or both of the magnet within the capsule main unit and the external magnet can be reduced in size. 
     Having described the preferred embodiments of the invention referring to the accompanying drawings, it should be understood that the present invention is not limited to those precise embodiments, and various changes, combinations, and modifications thereof could be made by one skilled in the art without departing form the spirit or scope of the invention as defined in the appended claims.