Patent Publication Number: US-2023158251-A1

Title: Indwelling needle

Description:
TECHNICAL FIELD 
     The present invention relates to an indwelling needle including an outer needle that is indwelled by puncturing a living body. 
     BACKGROUND ART 
     An indwelling needle has been developed as a medical instrument used for infusion such as drip infusion. The indwelling needle includes an inner needle that punctures a blood vessel of a patient, and an outer needle that is penetrated by the inner needle and is inserted into the blood vessel of the patient together with the inner needle as the inner needle punctures the living body. The outer needle is indwelled in the blood vessel of the patient, collecting blood from or giving a drip to the patient via the outer needle. As such an indwelling needle, Patent Literature 1 discloses an indwelling needle in which an outer needle hub is provided with a tube on its lateral side and a rubber stopper (the rubber stopper is also referred to as an elastic member) is provided at a proximal end of the outer needle hub. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: JP 2004-528127 A 
     SUMMARY OF INVENTION 
     Technical Problem 
     In the indwelling needle as described above, since there is a space between the rubber stopper and the tube in the outer needle hub, stagnation can occur in the vicinity of the rubber stopper. For this reason, for example, when the indwelling needle is used for an operation of allowing a liquid (blood) having a coagulation component to flow for a long time, such as artificial dialysis, blood clots may be generated in the vicinity of the rubber stopper. 
     Therefore, an object of the present invention is to provide an indwelling needle in which stagnation hardly occurs in the vicinity of an elastic member. 
     Solution to Problem 
     In order to achieve the above object, the present invention adopts the following configurations. 
     That is, an indwelling needle according to one aspect of the present invention includes: 
     an inner needle that punctures a living body; 
     an outer needle that is penetrated by the inner needle and is inserted into the living body together with the inner needle as the inner needle punctures the living body; 
     an outer needle hub including a main body that is arranged along an axis of the inner needle and a branch part that branches from the main body, the outer needle hub having a passage communicating with an inside of the outer needle; 
     an elastic member that is disposed inside the outer needle hub, is penetrated by the inner needle, and has a soft solid part that blocks a fluid flow to a proximal end side of the main body in a case where the inner needle is removed; and 
     a holder that is attached to a proximal end of the elastic member, wherein 
     the elastic member has an end surface that forms at least a part of the passage bringing the inside of the outer needle and the branch part into communication, and that is inclined with respect to a direction of the axis, and 
     the outer needle hub has a guiding part that is engaged with the elastic member or the holder to guide a direction around the axis of the elastic member in a certain direction. 
     In this way, the elastic member can be positioned by the guiding part in such a direction around the axis that the inclined surface is directed toward the branch part. The inclined surface of the elastic member can make the passage from a distal end of the outer needle hub to the branch part smoother than a conventional one. As a result, the fluidity of a liquid in the outer needle hub is improved, and the occurrence of stagnation in the vicinity of the elastic member is reduced. 
     In the present invention, the elastic member has a central part where the inclined end surface is formed, and an outer peripheral part formed on the outer peripheral side of the central part. A peripheral wall part having a proximal end surface facing a distal end surface of the outer peripheral part is formed on an inner surface of the outer needle hub. At least a part of the central part is located inside the peripheral wall part. In this way, a step is less likely to be formed between the elastic member and the peripheral wall part, and it is possible to suppress formation of a space that causes stagnation. 
     A guided part to be engaged with the guiding part of the present invention may be the inclined surface as the distal end surface of the elastic member, or may be a recess or a protrusion formed on an outer surface of the elastic member. The guided part may be formed on a distal end surface of the holder, or may be a recess or a protrusion formed on an outer surface of the holder. That is, the guiding part may be the peripheral wall part, or may be a protrusion or a recess extending in the axis direction. In addition, the guiding part may be a screw part that defines the direction around the axis in a certain direction. Furthermore, the guiding part is not limited to the inner surface of the outer needle hub, and may be provided on an outer surface of the outer needle hub. The guided part extending to the outer surface of the outer needle hub may be formed in the holder. In addition, an inclined surface having an inclination direction different from that of the inclined surface of the elastic member may be formed on the hub inner surface and the elastic member or the holder, and the direction around the axis of the elastic member may be set to a predetermined direction by overlapping the surfaces. 
     In the present invention, the end surface of the central part of the elastic member and an end surface of the peripheral wall part are formed to have a long axis and a short axis. In this way, the central part can be easily positioned in the peripheral wall part of the outer needle hub, and the elastic member can be easily defined in the predetermined direction around the axis. 
     In the present invention, the long axis of the central part of the elastic member is along an axis direction of the branch part. In this way, stagnation of a liquid can be made difficult to occur when the liquid moves from the branch part to the outer needle or from the outer needle to the branch part. 
     In the present invention, a step between the central part and the outer peripheral part of the elastic member is inclined. In this way, the central part can be easily located in the peripheral wall part, and a fixing force can be improved by increasing a contact area with the peripheral wall part. 
     In the present invention, a slit formed in the central part of the elastic member is a straight line along the long axis direction of the central part of the elastic member. 
     In the present invention, the proximal end of the elastic member is externally inserted onto the holder. In this way, when the elastic member is mounted to the outer needle hub, the elastic member is less likely to escape, and stable mounting can be achieved. A part of a proximal end surface of the elastic member may be a plane perpendicular to the axis direction. It is preferable to provide a surface to be engaged with the part of the proximal end surface of the elastic member, on the distal end surface of the holder, because the elastic member can be made less likely to be deformed when the elastic member is moved via the holder. 
     In the present invention, a part of the proximal end surface of the elastic member is an inclined surface inclined with respect to the axis direction, and the holder has an inclined surface that is engaged with the inclined surface. In this way, relative rotation between the elastic member and the holder can be suppressed. 
     In the present invention, a recess or a protrusion may be provided on a part of the proximal end surface of the elastic member, and a protrusion or a recess may be provided on the distal end surface of the holder to suppress relative rotation between the elastic member and the holder. In this way, relative rotation between the elastic member and the holder can be suppressed. 
     In the present invention, the guiding part is the proximal end surface formed in the peripheral wall part and inclined with respect to the axis direction, and the outer peripheral part has the distal end surface that is engaged with the proximal end surface of the peripheral wall part. 
     In this way, deformation of the elastic member in the proximal end direction is restricted by the holder. When the elastic member is pushed into the outer needle hub, the outer peripheral part and the peripheral wall part come into abutment to generate a guiding action in the direction around the axis in the elastic member. Since the guiding action is generated until the outer peripheral part and the peripheral wall part are engaged with each other, the elastic member is defined in the predetermined direction around the axis. 
     In the present invention, the guiding part is a rotation preventing mechanism that prevents rotation of the elastic member about the axis. 
     In the present invention, the holder includes a locking part that restricts relative movement in the axis direction with respect to the outer needle hub. 
     In the holder, means for restricting the relative movement in the axis direction with respect to the outer needle hub is not limited to the locking part, and the holder and the outer needle hub may be fixed to each other with an adhesive or the like. 
     In the present invention, the elastic member is compressed radially inward. Such compression prevents liquid leakage from the slit. Note that the compression may be performed by the outer needle hub or by the holder. 
     In the present invention, the central part is compressed inward by the peripheral wall part. 
     In the present invention, the holder has an annular step part adjacent to the central part of the elastic member. In this way, the central part of the elastic member that directly receives pressure from the liquid can be made less likely to be deformed toward the proximal end side, and a stagnation space can be made less likely to be generated on the distal end side of the elastic member. 
     In the present invention, the elastic member has a cylindrical part extending from the outer peripheral part toward the proximal end, and the holder has a small diameter part inserted into the cylindrical part and a large diameter part abutting on a proximal end of the cylindrical part. In this way, the elastic member can be stably mounted to the holder. In addition, the thickness of the holder can be reduced to decrease a necessary external force in pulling out the inner needle. 
     In the present invention, the peripheral wall part and a distal end part of the holder face each other to compress the elastic member in the axis direction. 
     In the present invention, 
     the holder includes an attachment-target part to which the elastic member is attached, and 
     the elastic member includes, on a proximal end side of the solid part, a cylindrical part whose inner diameter side is supported by the attachment-target part, the cylindrical part having a radial thickness larger than an interval between the attachment-target part and a surface of the outer needle hub radially facing the attachment-target part in a state before being mounted to the outer needle hub. 
     In this way, a gap between the elastic member and the surface of the outer needle hub on which the elastic member is disposed is sealed by the cylindrical part compressed between the attachment-target part of the holder and the surface of the outer needle hub, so that it is possible to prevent the fluid from flowing to the proximal end side of the main body through between the elastic member and the surface of the outer needle hub on which the elastic member is disposed. 
     The radial thickness of the cylindrical part is not limited to a case where the thickness is constant in the axis direction, and at least a part of the cylindrical part in the axis direction may have a radial thickness larger than the interval between the attachment-target part and the surface of the outer needle hub radially facing the attachment-target part. 
     That is, an indwelling needle according to one aspect of the present invention includes: 
     an inner needle that punctures a living body; 
     an outer needle that is penetrated by the inner needle and is inserted into the living body together with the inner needle as the inner needle punctures the living body; 
     an outer needle hub including a main body that is arranged along an axis of the inner needle and a branch part that branches from the main body, the outer needle hub having a passage communicating with an inside of the outer needle; and 
     an elastic member that is disposed inside the outer needle hub, is penetrated by the inner needle, and has a soft solid part that blocks a fluid flow to a proximal end side of the main body in a case where the inner needle is removed, wherein 
     the elastic member has an end surface that forms at least a part of the passage bringing the inside of the outer needle and the branch part into communication, and that is inclined with respect to a direction of the axis, and 
     the outer needle hub has a guiding part that is engaged with the elastic member to guide a direction around the axis of the elastic member in a certain direction. 
     In this way, the elastic member can be positioned by the guiding part in such a direction around the axis that the inclined surface is directed toward the branch part. The inclined surface of the elastic member can make the passage from a distal end of the outer needle hub to the branch part smoother than a conventional one. As a result, the fluidity of a liquid in the outer needle hub is improved, and the occurrence of stagnation in the vicinity of the elastic member is reduced. 
     That is, an indwelling needle according to one aspect of the present invention includes: 
     an inner needle that punctures a living body; 
     an outer needle that is penetrated by the inner needle and is inserted into the living body together with the inner needle as the inner needle punctures the living body; 
     an outer needle hub including a main body that is arranged along an axis of the inner needle and a branch part that branches from the main body, the outer needle hub having a passage communicating with an inside of the outer needle; and 
     an elastic member that is disposed inside the outer needle hub, is penetrated by the inner needle, and has a soft solid part that blocks a fluid flow to a proximal end side of the main body in a case where the inner needle is removed, wherein 
     the elastic member has a central part having an end surface that forms at least a part of the passage bringing the inside of the outer needle and the branch part into communication, and that is inclined with respect to a direction of the axis, and an outer peripheral part, and 
     a peripheral wall part having a proximal end surface facing a distal end surface of the outer peripheral part is formed on an inner surface of the outer needle hub, and at least a part of the central part is located inside the peripheral wall part. 
     In this way, it is possible to provide the indwelling needle in which stagnation hardly occurs in the vicinity of the elastic member by suppressing formation of a space where stagnation occurs on the distal end side of the elastic member. 
     The present invention includes 
     a holder that is attached to a proximal end of the elastic member and includes an attachment-target part to which the elastic member is attached, wherein 
     the elastic member includes, on a proximal end side of the solid part, a cylindrical part whose inner diameter side is supported by the attachment-target part, the cylindrical part having a radial thickness larger than an interval between the attachment-target part and a surface of the outer needle hub radially facing the attachment-target part in a state before being mounted to the outer needle hub. 
     In this way, a gap between the elastic member and the surface of the outer needle hub on which the elastic member is disposed is sealed by the cylindrical part compressed between the attachment-target part of the holder and the surface of the outer needle hub, so that it is possible to prevent the fluid from flowing to the proximal end side of the main body through between the elastic member and the surface of the outer needle hub on which the elastic member is disposed. 
     The radial thickness of the cylindrical part is not limited to a case where the thickness is constant in the axis direction, and at least a part of the cylindrical part in the axis direction may have a radial thickness larger than the interval between the attachment-target part and the surface of the outer needle hub radially facing the attachment-target part. 
     Advantageous Effects of Invention 
     According to the present invention, it is possible to provide the indwelling needle in which stagnation hardly occurs in the vicinity of the elastic member. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a side view of an indwelling needle of a first embodiment. 
         FIG.  2    is a cross-sectional view taken along a direction A-A in  FIG.  1   . 
         FIG.  3    is a cross-sectional view taken along a direction B-B in  FIG.  2   . 
         FIG.  4    is an enlarged view of a main part of  FIG.  3   . 
         FIG.  5    is a cross-sectional view taken along a direction D-D in  FIG.  1   . 
         FIG.  6    is an exploded perspective view including an outer needle hub, a hemostasis valve, and a hemostasis valve holder of the first embodiment. 
         FIGS.  7 (A) to  7 (D)  are drawings illustrating a configuration of an outer needle hub to which a hemostasis valve holder is mounted according to a third modification. 
         FIG.  8    is a side view of the hemostasis valve holder of the third modification. 
         FIGS.  9 (A) to  9 (D)  are drawings illustrating a configuration of an outer needle hub to which a hemostasis valve holder is mounted according to a fourth modification. 
         FIGS.  10 (A) and  10 (B)  are a side view and an end view of the hemostasis valve holder of the fourth modification. 
         FIG.  11    is an exploded perspective view of an outer needle hub, a hemostasis valve, and a hemostasis valve holder of a second embodiment. 
         FIGS.  12 (A) to  12 (E)  are drawings illustrating a configuration of the outer needle hub to which the hemostasis valve and the hemostasis valve holder are mounted according to the second embodiment. 
         FIGS.  13 (A) to  13 (D)  are drawings illustrating a configuration of an outer needle hub to which a hemostasis valve and a hemostasis valve holder are mounted according to a fifth modification. 
         FIG.  14    is a drawing illustrating a configuration of an outer needle hub to which a hemostasis valve holder is mounted according to a sixth modification. 
         FIG.  15    is a side view and an end view of the hemostasis valve holder of the sixth modification. 
         FIG.  16    is a plan view of an outer needle hub of a seventh modification. 
         FIG.  17    is a cross-sectional view taken along a direction C-C in  FIG.  16   . 
         FIG.  18    is a cross-sectional view taken along a direction E-E in  FIG.  17    according to the seventh modification. 
         FIG.  19    is an exploded perspective view of another modification. 
         FIGS.  20 (A) and  20 (B)  are a plan view and an A-A cross-sectional view of an outer needle hub to which a hemostasis valve holder is mounted according to a third embodiment. 
         FIGS.  21 (A) and  21 (B)  are a side view and a B-B cross-sectional view of the outer needle hub to which the hemostasis valve holder is mounted according to the third embodiment. 
         FIGS.  22 (A) and  22 (B)  are a perspective view and an A-A cross-sectional view of a hemostasis valve of the third embodiment. 
         FIGS.  23 (A) and  23 (B)  are side views of the hemostasis valve holder of the third embodiment and that of a reference example. 
         FIGS.  24 (A) and  24 (B)  are an A-A cross-sectional view and a B-B cross-sectional view of an outer needle hub to which the hemostasis valve holder is mounted according to the reference example. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, modes for carrying out the present invention will be exemplarily described in detail based on embodiments with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of components described in the embodiments should be changed as appropriate according to the configuration of a device to which the invention is applied and various conditions. That is, the scope of the present invention is not intended to be limited to the following embodiments. 
     First Embodiment 
     &lt;Outline of Indwelling Needle&gt; 
       FIG.  1    illustrates a side view of an indwelling needle  1  according to an embodiment of the present invention.  FIG.  2    is a cross-sectional view taken along a direction A-A of the indwelling needle  1  in  FIG.  1   .  FIG.  3    is a cross-sectional view taken along a direction B-B in  FIG.  2    of the indwelling needle  1  illustrated in  FIG.  1   . 
     First, the outline of the indwelling needle  1  will be described with reference to  FIG.  1   . As illustrated in  FIG.  1   , the indwelling needle  1  includes a hollow inner needle  2  and a cylindrical outer needle  3  provided to cover an outer surface of the inner needle  2 . The inner needle  2  protrudes from an opening at a distal end of the outer needle  3 , and punctures a blood vessel of a patient (living body) as a puncture object. In the following description, an end (side/direction) of the indwelling needle  1  from which the inner needle  2  protrudes is referred to as a distal end (side/direction), and an opposite end is referred to as a rear end (side/direction) or a proximal end (side/direction). A direction in which the inner needle  2  protrudes is also referred to as a puncture direction. 
     An outer needle hub  4  is also connected to a rear end of the outer needle  3 . A hollow portion communicating with a hollow portion  31  of the outer needle  3  is provided inside the outer needle hub  4  (see  FIG.  4   ). As illustrated in  FIG.  1   , the outer needle hub  4  includes a main body  40  extending linearly in the puncture direction, that is, a direction of an axis L 1 , which will be described later, of the inner needle  2 , and a substantially cylindrical branch part  41  branching in a Y-shape in a direction opposite to the puncture direction from the main body  40 , that is, in a direction inclined with respect to the direction of the axis L 1  of the inner needle  2  ( FIG.  4    illustrates an axis L 2  of the branch part  41 .). A hollow portion  400  and a hollow portion  405  are provided inside the main body  40  (see  FIG.  4   ). A hollow portion  410  is also provided inside the branch part  41  (see  FIG.  4   ). The hollow portion  31  of the outer needle, the hollow portions  400  and  405  of the main body  40 , and the hollow portion  410  of the branch part  41  communicate with each other. When the inner needle  2  is removed from the outer needle  3 , a passage is formed that brings the hollow portion  31  of the outer needle  3 , the hollow portion  400  of the main body  40 , and the hollow portion  410  of the branch part  41  into communication. A second end surface  63  of a hemostasis valve  6 , which will be described later, forms a part of the passage. The outer needle hub  4  can be formed of, for example, a resin such as polypropylene, and is not particularly limited as long as a material typically used for medical instruments is used. Note that the outer needle hub  4  may be formed of a single member or a plurality of members. In addition, a flexible soft tube may be disposed between a distal end and a proximal end of the outer needle hub  4 . Furthermore, the outer needle hub  4  is not limited to the Y-shape, and may be, for example, an L-shape. Moreover, the branch part  41  may extend in a left-right direction instead of extending to the top side. 
     An extension tube through which, for example, blood supplied from an external apparatus such as an artificial dialysis apparatus passes is connected to a rear end of the branch part  41  in the indwelling needle  1 . Note that a connector may be provided at a port end without providing the extension tube. Here, the blood corresponds to a fluid of the present invention. 
     A hemostasis valve holder  5  that supports the hemostasis valve  6  described later, and an inner needle hub  21  that holds a rear end of the inner needle  2  are connected to a rear end of the main body  40  in the indwelling needle  1 . Here, the hemostasis valve  6  and the hemostasis valve holder  5  correspond to an elastic member and a support member of the present invention, respectively. 
     A pair of wings  7  is provided on the outer periphery near a distal end of the main body  40  in the indwelling needle so as to sandwich the main body  40 . The wings  7  include a cylindrical sleeve  70  fitted and attached to the outer periphery near the distal end of the main body  40 , and plate-like parts  71  protruding from side surfaces of the sleeve  70  in a direction perpendicular to the axis direction (the front side and the back side of the drawing). The sleeve  70  is fixed so as not to move axially nor around the axis with respect to the main body. The wings  7  function as a gripping part for an operator to grip when he/she uses the indwelling needle  1 , and also function as a fixing part for fixing the indwelling needle  1  to a body with a tape or the like. Although the wings extend in a direction intersecting the extending direction of the branch part, the wings may extend in a direction parallel to the branch part. In addition, the sleeve  70  may be provided so as to be relatively rotatable in a direction around the axis with respect to the main body. In this case, a user can place the wings at a suitable position. Furthermore, the wings do not have to be provided. 
     &lt;Internal Configuration of Indwelling Needle&gt; 
     Next, the details of the inside of the indwelling needle  1  will be described using  FIGS.  2  and  3   . As illustrated in  FIG.  2   , an outer needle holding part  401  that holds the proximal end side of the outer needle  3  is provided on the distal end side of the main body  40  of the outer needle hub  4 . A distal end opening  402  that opens in the puncture direction is provided at a distal end of the outer needle holding part  401 . The outer needle  3  is held by the outer needle holding part  401  such that its distal end protrudes from the distal end opening  402 . The proximal end side of the outer needle  3  is fixed by a caulking pin  403  filling a space between the outer needle  3  and the outer needle hub  4 . 
     In addition, the hemostasis valve  6  is attached to a distal end of the hemostasis valve holder  5 . The inner needle hub  21  is connected to a rear end side of the hemostasis valve holder  5 . The inner needle hub  21  holds the proximal end side of the inner needle  2  on its distal end side. A protector  8  for protecting a needle tip  2   a  of the inner needle  2  is attached to the distal end side of the inner needle hub  21 . The protector  8  includes a protector body  80  and a protector holder  81 . 
     The protector body  80  is configured to cover and protect the needle tip  2   a  of the inner needle  2 , and is made of various metal materials such as stainless steel, aluminum, an aluminum alloy, a titanium alloy, copper, a copper alloy, and a copper-based alloy, for example. The protector body  80  can be configured as, for example, a substantially quadrangular prism-shaped member obtained by bending and deforming a thin plate made of the above-described metal material. As illustrated in  FIG.  3   , the protector body  80  mainly includes a substantially square bottom plate part  80   a  and flexible protective pieces  80   b  and  80   c  extending from two opposing sides of the bottom plate part  80   a  toward a distal end. The inner needle  2  is inserted into a hole opened at the center of the bottom plate part  80   a , and the protector body  80  is supported so as to be movable in the axis direction of the inner needle  2 . The protective piece  80   b  and the protective piece  80   c  are substantially rectangular plate-like members, and face each other with the inner needle  2  interposed therebetween. The protective piece  80   b  and the protective piece  80   c  have a substantially J-shape in which the pieces are bent in a direction away from each other from the bottom plate part  80   a  toward the distal end side (an outer diameter direction of the inner needle  2 ), then bent in a direction approaching each other (an inner diameter direction of the inner needle  2 ), and bent in a direction approaching each other toward the rear end side on the distal end side. The protective piece  80   b  is formed to be longer than the protective piece  80   c , and a distal end part of the protective piece  80   b  is located closer to the distal end than a distal end part of the protective piece  80   c.    
     The protector holder  81  is a substantially cylindrical member made of a synthetic resin. The protector holder  81  has a cylindrical part  81   a  on the distal end side, a housing part  81   b  on the rear end side, and a ring part  81   c  at a rear end part of the housing part  81   b . The cylindrical part  81   a  is formed in a substantially cylindrical shape. The cylindrical part  81   a  is inserted from an opening on the rear end side of the hemostasis valve holder  5 , is housed in a hollow portion of the hemostasis valve holder  5 , and is locked to the hemostasis valve holder  5  by engagement means such as unevenness (not illustrated). The housing part  81   b  is formed in a quadrangular tube shape having a substantially square cross section, and its distal end side is formed integrally with a rear end of the cylindrical part  81   a . Substantially rectangular openings are formed in a pair of opposing side walls (two side walls in a top-bottom direction in  FIG.  3   ) of the housing part  81   b . These openings are provided on the side opposite to the inner needle  2  with respect to the protective piece  80   b  and the protective piece  80   c . These openings allow deformation of the protective piece  80   b  and the protective piece  80   c  in the direction away from each other. 
     In addition, the ring part  81   c  is formed in an annular shape having a square cross section composed of four side walls. The dimensions of an inner peripheral part of the ring part  81   c  are formed to substantially coincide with the outer dimensions of the bottom plate part  80   a  of the protector body  80 . As a result, when the protector body  80  is moved so as to be pulled out from the ring part  81   c , inserting the protective piece  80   b  and the protective piece  80   c  of the protector body  80  into the ring part  81   c , the protective piece  80   b  and the protective piece  80   c  are pushed inward by the ring part  81   c . By being pushed inward, the protective piece  80   b  and the protective piece  80   c  are elastically deformed so as to approach each other, and the protective piece  80   b  and the protective piece  80   c  facing each other come into abutment with each other, thereby closing a gap therebetween. At this time, deformed portions of the protective piece  80   b  and the protective piece  80   c  protrude from the openings of the housing part  81   b . The protective piece  80   b  and the protective piece  80   c  cannot move in the direction of approaching each other any more as described above. Therefore, the movement of the protector body  80  is restricted by rear end side portions of the protective piece  80   b  and the protective piece  80   c , and the protector body  80  cannot be removed from the protector holder  81 . In this way, by moving the protector body  80  in the direction of pulling out the protector body  80  from the protector holder  81 , the needle tip  2   a  of the inner needle  2  is covered and protected by the protector body  80 , and cannot move relative to the protector holder  81 , whereby the protected state is maintained. 
     When the outer needle  3  is indwelled in the body and the inner needle hub  21  is pulled out from the outer needle hub  4 , an engagement part provided on the distal end side of the inner needle  2  and the bottom plate part  80   a  of the protector body  80  are engaged with each other since at least a part of the outer diameter of the engagement part is set to be larger than the inner diameter of the hole opened in the bottom plate part  80   a . When the inner needle hub  21  is further pulled out, the protector body  80  including the bottom plate part  80   a  engaged with the inner needle  2  moves to the rear end side. When the inner needle hub  21  is further pulled out, the protector body  80  moves to the rear end side relative to the protector holder  81  as described above. Therefore, the protective piece  80   b  and the protective piece  80   c  abutting on each other can cover and protect the needle tip  2   a  of the inner needle  2 . 
     &lt;Configuration of Main Part&gt; 
       FIG.  4    is an enlarged view illustrating a main part of the cross-sectional view illustrated in  FIG.  3   .  FIG.  5    is a cross-sectional view taken along a direction D-D in  FIG.  1   .  FIG.  6    is an exploded perspective view of the outer needle hub  4 , the hemostasis valve  6 , and the hemostasis valve holder  5 . The axis L 1  is a line indicating the axis direction of the main body  40  of the outer needle hub  4 , and coincides with the axis of the inner needle  2  in a state where the inner needle  2  is inserted into the outer needle  3 . 
     As illustrated in  FIG.  4   , the outer needle hub  4  is provided with the hollow portion  400  communicating with the hollow portion  31  of the outer needle  3 . The hollow portion  405  on the rear end side in the axis L 1  direction from the hollow portion  400  and the hollow portion  410  inclined with respect to the axis L 1  direction from the hollow portion  400  communicate with each other via the hollow portion  400 . 
     The hemostasis valve  6  and the hemostasis valve holder  5  are attached to the hollow portion  405 . The inner needle hub  21  equipped with the protector  8  is attached to the rear end side of the hemostasis valve holder  5 . At this time, the inner needle  2  pushes open a slit  64  of the hemostasis valve  6  to be inserted into the hollow portion  31  of the outer needle  3 . The hemostasis valve  6  is formed of, for example, synthetic rubber such as polyisoprene, or thermoplastic elastomer. The hemostasis valve holder  5  can be formed of, for example, a resin such as polypropylene, and is not particularly limited as long as a material typically used for medical instruments is used. 
     As illustrated in  FIG.  6   , the hemostasis valve  6  is formed in a substantially bottomed cylindrical shape. An end part on the distal end side of the hemostasis valve  6  is formed in an inclined surface inclined with respect to the axis L 1  direction. Specifically, the hemostasis valve  6  includes a cylindrical part  60 , an annular first end surface  61  connected to an end edge on the distal end side of the cylindrical part  60 , an annular step part  62  connected to the inner diameter side of the first end surface  61  and extending in the axis L 1  direction, and a disk-shaped second end surface  63  connected to the inner diameter side of the step part  62 . The first end surface  61  and the second end surface  63  of the hemostasis valve  6  are configured to be substantially parallel, and are similarly inclined with respect to the axis L 1  direction. The linear slit  64  penetrating a soft solid part  631  from the distal end side to the rear end side is opened at the center of the second end surface  63 . Note that the slit may also have a cross shape, a Y-shape, or the like. In addition, a central proximal end surface  66 , which is a surface on the rear end side of the first end surface  61  and the second end surface  63  of the hemostasis valve  6 , is formed as a single surface parallel to the first end surface  61 . The shape of the second end surface  63  of the hemostasis valve  6  is not limited to a flat surface, and may be formed into a curved surface conforming to the shape of a cylindrical surface of a peripheral wall of the hollow portion  410  of the branch part  41 . It can also be said that the second end surface  63  is a central part of the hemostasis valve  6 , and the first end surface  61  is an outer peripheral part formed on the outer periphery of the central part. In addition, in the hemostasis valve  6 , the second end surface  63  and the step part  62  may be formed in a shape in which a straight line La indicated by a dotted line in  FIG.  4    is a long axis and a straight line Sa is a short axis. At this time, an opening  404  of the outer needle hub  4  is similarly formed in a shape having a long axis and a short axis. The central part of the hemostasis valve  6  and the opening  404  of the outer needle hub  4  have the long axes and the short axes, to function as an outer peripheral part and a guided part, so that the hemostasis valve  6  can be easily positioned in a predetermined direction around the axis. In addition, in a case where the second end surface  63  and the step part  62  are formed in the shape having the long axis and the short axis as described above, it is desirable to set the long axis in a direction along the axis L 2  direction of the branch part  41  from the viewpoint of miniaturization. Furthermore, when the second end surface  63  has the shape having the long axis and the short axis as described above, it is desirable to form the linear slit along the long axis direction. The step part  62  formed between the first end surface  61  and the second end surface  63  is inclined with respect to the axis L 1  direction, and is easily inserted when the central part of the hemostasis valve  6  is inserted into the opening  404  of the outer needle hub  4 . In addition, the hemostasis valve  6  is opened in a cylindrical shape on the rear end side, and the center is thinned relative to the outer peripheral part to reduce resistance at the time of pulling out the inner needle. An end surface  65  on the rear end side of the hemostasis valve  6  forms a plane perpendicular to the axis L 1  direction, and abuts on a step part  52   a  of the hemostasis valve holder  5 . In this way, it is possible to reduce unintentional deformation of an elastic valve body when the hemostasis valve  6  is relatively moved in the outer needle hub. 
     The hemostasis valve holder  5  is formed in a substantially cylindrical shape. The hemostasis valve holder  5  includes a small diameter part  51 , a diameter expanded part  52 , a large diameter part  53 , and a flange part  54  sequentially from the distal end side. An annular first end surface  51   a  that is connected to the inner diameter side of an end edge of the small diameter part  51  and is inclined with respect to the axis L 1  direction is formed at an end part on the distal end side of the small diameter part  51 . An annular step part  51   b  is formed that is connected to the inner diameter side of the first end surface  51   a  and extends in the axis L 1  direction. A second end surface  51   c  is also formed that is connected to the inner diameter side of the step part and is inclined with respect to the axis L 1  direction. The first end surface  51   a  and the second end surface  51   c  of the hemostasis valve holder  5  are configured to be substantially parallel, and are similarly inclined with respect to the axis L 1  direction. In addition, the first end surface  51   a  and the second end surface  51   c  of the hemostasis valve holder  5  are configured to be parallel to the first end surface  61  and the second end surface  63  of the hemostasis valve  6 , respectively, and are similarly inclined with respect to the axis L 1  direction. Here, the annular step part  51   b  may be provided so as to be inclined with respect to the axis L 1  direction in order to increase a contact area with the hemostasis valve  6 . In addition, a distal end part of the second end surface  51   c  is desirably formed in a rounded shape. 
     In the hemostasis valve holder  5 , the rear end side of the small diameter part  51  is connected to the diameter expanded part  52  having a diameter increasing toward the rear end side via the step part  52   a  extending to the outer diameter side, that is, in a direction perpendicular to the axis L 1 . The rear end side of the diameter expanded part  52  is connected to the large diameter part  53 . The annular flange part  54  protruding to the outer diameter side is formed on the rear end side of the large diameter part  53 . Formed on side surfaces of the large diameter part  53  are a protrusion  55   a  and a protrusion  55   b  (see  FIG.  5   ) that protrude to the outer diameter side gradually from the distal end side toward the rear end side. The protrusion  55   a  and the protrusion  55   b  are provided at symmetrical positions with respect to the axis L 1 . A rib  56  protruding to the outer diameter side and extending in the axis L 1  direction from the distal end side toward the rear end side is also formed on the side surface of the large diameter part  53 , and the rear end side of the rib  56  is connected to the flange part  54 . The rib  56  is provided between the protrusion  55   a  and the protrusion  55   b , and is provided at a position opposite to the branch part  41  with respect to the axis L 1  direction in relation with the outer needle hub  4 . 
     The outer diameter dimension of the small diameter part  51  of the hemostasis valve holder  5  is set to be slightly smaller than the inner diameter dimension of the cylindrical part  60  of the hemostasis valve  6 . When the small diameter part  51  of the hemostasis valve holder  5  is fitted into the inner periphery of the cylindrical part  60  of the hemostasis valve  6  from the distal end side, the cylindrical part  60  of the hemostasis valve  6  slightly increases in diameter to the outer diameter side, but tries to decrease in diameter to be elastically deformed. The elastic deformation produces a frictional force between an inner peripheral surface of the cylindrical part  60  of the hemostasis valve  6  and an outer peripheral surface of the small diameter part  51  of the hemostasis valve holder  5 . Since the first end surface  51   a , which is a distal end surface of the hemostasis valve holder  5 , is inclined with respect to the axis direction similarly to the central proximal end surface  66  of the hemostasis valve  6 , the first end surface  51   a  restricts displacement of the hemostasis valve  6  with respect to the hemostasis valve holder  5  in the axis L 1  direction and a rotation direction about the axis L 1 , and the first end surface  51   a  also functions as a guide in mounting the hemostasis valve  6  and the hemostasis valve holder  5  in a predetermined direction around the axis. The dimensions in the axis L 1  direction of the cylindrical part  60  of the hemostasis valve  6  and the small diameter part  51  of the hemostasis valve holder  5  are set such that the end surface  65  on the rear end side of the cylindrical part  60  of the hemostasis valve  6  abuts on the step part  52   a  of the hemostasis valve holder  5  in a state where the first end surface  51   a  of the small diameter part  51  of the hemostasis valve holder  5  abuts on the rear end side of the first end surface  61  and the second end surface  63  of the hemostasis valve  6 . When the small diameter part  51  of the hemostasis valve holder  5  is pushed into the hemostasis valve  6  to a position where the step part  52   a  of the hemostasis valve holder  5  abuts on the end surface on the rear end side of the cylindrical part  60  of the hemostasis valve  6 , the step part  51   b  and the second end surface  51   c  of the small diameter part  51  of the hemostasis valve holder  5  slightly bite into the rear end side of the second end surface  63  of the hemostasis valve  6 . A hollow portion of the hemostasis valve  6  and the small diameter part  51  of the hemostasis valve holder  5  are configured in shapes rotationally asymmetric to each other with respect to the axis L 1 . Thus, the rotation of the hemostasis valve  6  about the axis L 1  with respect to the hemostasis valve holder  5  is restricted in a state where the hemostasis valve  6  is attached to a predetermined position of the small diameter part  51  of the hemostasis valve holder  5 . Such a rotation preventing mechanism that restricts relative rotation between the hemostasis valve holder  5  and the hemostasis valve  6  is provided, so that it is possible to reduce the occurrence of displacement of the hemostasis valve at the time of mounting. Note that the shape of the small diameter part of the hemostasis valve holder  5  is not limited to the cylindrical shape. 
       FIG.  4    illustrates a state in which the hemostasis valve  6  and the hemostasis valve holder  5  are appropriately positioned with respect to the outer needle hub  4 . The opening  404  is provided on the distal end side of the hollow portion  405  of the main body  40  of the outer needle hub  4  via a step part  406 . The inner diameter of the opening  404  in the direction perpendicular to the axis L 1  is set to be smaller than the inner diameter of the hollow portion  405 . The inner diameter of the hollow portion  405  is set such that an outer peripheral surface of the hemostasis valve holder  5  to which the hemostasis valve  6  is attached is in pressure contact with an inner peripheral surface of the hollow portion  405  to block the flow of a liquid such as blood through the outer peripheral sides of the hemostasis valve  6  and the hemostasis valve holder  5  between the hollow portion  400  and the hollow portion  405 . To this end, the inner peripheral surface on the distal end side of the hollow portion  405  is formed in a cylindrical shape corresponding to the cylindrical part  60  of the hemostasis valve  6 , the rear end side thereof is formed in a tapered shape having a diameter increasing to the outer diameter side toward the rear end side corresponding to the diameter expanded part  52  of the hemostasis valve holder  5 , and the further rear end side thereof is formed in a cylindrical shape corresponding to the large diameter part  53  of the hemostasis valve holder  5 . Note that a portion including the step part  406  and the opening  404  of the outer needle hub  4  may be formed as a separate member from the other portions of the outer needle hub  4 , and may be integrated by fixing the separate member to the outer needle hub  4 . 
     When the hemostasis valve  6  and the hemostasis valve holder  5  are appropriately positioned with respect to the outer needle hub  4  as illustrated in  FIG.  4   , the first end surface  61  and the step part  62  of the hemostasis valve  6  abut on inner peripheral surfaces of the step part  406  and the opening  404  of the outer needle hub  4 , respectively, and the hemostasis valve  6  is compressively fixed in the axis L 1  direction between the step part  406  of the outer needle hub  4  and the first end surface  51   a  of the hemostasis valve holder  5  facing each other. The second end surface  63  of the hemostasis valve  6  is exposed to the hollow portion  400 . The second end surface  63  of the hemostasis valve  6  is set to substantially the same height as a portion adjacent to the opening  404  in an inner peripheral surface of the hollow portion  410  of the branch part  41 . As described above, in the hemostasis valve  6 , the outer peripheral part is firmly fixed, and the central part fills an air gap in the outer needle hub  4 . In the hollow portion  410  branching from the hollow portion  400 , there is no rapid shape change in a part of the second end surface  63  of the hemostasis valve  6  constituting a part of the inner peripheral surface of the hollow portion  410 . Therefore, a liquid such as blood smoothly flows in the hollow portion  31  of the outer needle  3 , and the hollow portion  400  of the main body  40  and the hollow portion  410  of the branch part  41  of the outer needle hub  4 , generating no stagnation that causes blood clots. The step part  406  and the opening  404  of the outer needle hub  4  function as a peripheral wall part for the second end surface  63  as the central part on the distal end side of the hemostasis valve  6 , and the step part  406  constitutes a proximal end surface of the peripheral wall part engaged with the first end surface. The step part  406  inclined with respect to the axis L 1  direction constitutes a guiding part, and the distal end surface of the hemostasis valve  6  constitutes a guided part. 
     In addition, when the hemostasis valve  6  is appropriately positioned with respect to the outer needle hub  4 , an interval between parts  62   a  and  62   b  facing each other across the slit  64 , of the step part  62  of the hemostasis valve  6  is set to be slightly larger than the inner diameter of a corresponding part of the opening  404 , and a portion of the hemostasis valve  6  including these parts  62   a  and  62   b  is interference-fitted to the opening  404 . With this setting, a compressive force in a direction in which the slit  64  of the hemostasis valve  6  is closed is applied by the opening  404  of the outer needle hub  4 , so that an elastic return force of the slit  64  at the time of removing the inner needle  2  and after removing the inner needle  2  is increased, and the sealing property of the hemostasis valve  6  can be ensured. 
     In the above embodiment, the hemostasis valve  6  is compressed to the inner diameter side by the inner periphery of the opening  404  as described above. However, the compression mode is not limited to the above mode. For example, it is also possible to ensure the sealing property of the hemostasis valve  6  by forming the hemostasis valve  6  to be thick such that the central proximal end surface  66  of the hemostasis valve  6  is perpendicular to the axis direction, and compressing the hemostasis valve  6  radially inward from the outer needle hub  4 . In addition, the thickness of the hemostasis valve  6  can be further increased to ensure the sealing property of the hemostasis valve  6  without compressing the hemostasis valve  6 . Furthermore, an inclined surface inclined with respect to the axis direction may be provided at a contact part of the hemostasis valve holder  5  with the outer needle hub  4 , and an inclined surface engaged with the inclined surface may be provided on an inner surface of the outer needle hub  4 , to constitute the guiding part and the guided part, and the direction around the axis of the outer needle hub  4  and the hemostasis valve holder  5  may be set as a prescribed direction. 
     An opening  42   a  and an opening  42   b  having a rectangular shape are opened on side surfaces on the rear end side of the main body  40  of the outer needle hub  4 . The opening  42   a  and the opening  42   b  are provided at symmetrical positions with respect to the axis L 1 . In addition, a cutout  43  whose rear end side is released is opened on the rear end side of the main body  40  of the outer needle hub  4 . The cutout  43  is provided between the opening  42   a  and the opening  42   b , and is provided at a position opposite to the branch part  41  with respect to the axis L 1 . 
     When the hemostasis valve holder  5  to which the hemostasis valve  6  is attached is press-fitted from an opening on the rear end side of the outer needle hub  4  to be attached to the outer needle hub  4 , the protrusion  55   a , the protrusion  55   b , and the rib  56  of the hemostasis valve holder  5  are held in a posture corresponding to the opening  42   a , the opening  42   b , and the cutout  43  of the outer needle hub  4 . The hemostasis valve holder  5  is advanced in the axis L 1  direction with respect to the outer needle hub  4  to be press-fitted from the opening on the rear end side, and the protrusion  55   a , the protrusion  55   b , and the rib  56  are fitted to the opening  42   a , the opening  42   b , and the cutout  43 , respectively. At this time, since the cutout  43  and the rib  56  extend in the axis L 1  direction, the hemostasis valve holder  5  is guided in the axis L 1  direction with respect to the outer needle hub  4  by the cutout  43  and the rib  56 . 
     In this way, the direction around the axis L 1  of the hemostasis valve  6  and the hemostasis valve holder  5  with respect to the outer needle hub  4  when the hemostasis valve  6  and the hemostasis valve holder  5  are attached to the outer needle hub  4  can be set to a predetermined direction. That is, the direction around the axis L 1  of the hemostasis valve  6  and the hemostasis valve holder can be guided in a certain direction, whereby the direction around the axis L 1  of the hemostasis valve  6  attached to the hemostasis valve holder  5  can be defined. By providing the rotation preventing mechanism including the protrusion  55   a , the protrusion  55   b , the rib  56 , the opening  42   a , the opening  42   b , and the cutout  43  as described above, it is possible to prevent the hemostasis valve  6  and the hemostasis valve holder  5  from rotating about the axis L 1  with respect to the outer needle hub  4 . Note that the rotation preventing mechanism may be composed of only the rib  56  and the cutout  43 . In addition, the protrusion  55   a  and the protrusion  55   b  of the hemostasis valve holder  5  are fitted to the opening  42   a  and the opening  42   b  of the outer needle hub  4  to constitute a locking part that restricts relative movement in the axis L 1  direction with respect to the outer needle hub  4 . 
     First Modification 
     In the above-described embodiment, the example has been described in which the rotation preventing mechanism in attaching the hemostasis valve  6  and the hemostasis valve holder  5  to the outer needle hub  4  is provided in the hemostasis valve holder  5  and the outer needle hub  4 . Here, the protrusion  55   a , the protrusion  55   b , and the rib  56  are provided in the hemostasis valve holder  5 , and the opening  42   a , the opening  42   b , and the cutout  43  are provided in the outer needle hub  4 . On the other hand, an opening, a cutout, or a recess may be provided in the hemostasis valve holder  5 , and a protrusion or a rib may be provided on the inner peripheral surface of the hollow portion  405  of the outer needle hub  4 . 
     Second Modification 
     In the modification of the above-described embodiment, the central proximal end surface  66  of the hemostasis valve  6  and the first end surface  51   a  at the distal end of the hemostasis valve holder  5  are inclined, restricting the relative rotation between the hemostasis valve  6  and the hemostasis valve holder  5 . However, the central proximal end surface  66  of the hemostasis valve  6  and the first end surface  51   a  at the distal end of the hemostasis valve holder  5  do not have to be inclined. The relative rotation may be restricted by providing a cutout, a recess, a protrusion, or the like in the hemostasis valve and providing a protrusion or the like engaged with the cutout, the recess, or the protrusion in the hemostasis valve holder. In addition, by roughening one or both of the inner peripheral surface of the cylindrical part  60  of the hemostasis valve  6  and the outer peripheral surface of the small diameter part  51  of the hemostasis valve holder  5 , a frictional force may be applied between the hemostasis valve  6  and the small diameter part  51  of the hemostasis valve holder  5 . Furthermore, the hemostasis valve  6  and the small diameter part  51  of the hemostasis valve holder  5  may be formed of materials that generate a frictional force with each other. A member that generates a frictional force may be interposed between the hemostasis valve  6  and the small diameter part  51  of the hemostasis valve holder  5 . The hemostasis valve  6  and the small diameter part  51  of the hemostasis valve holder  5  may be fixed with an adhesive. The cause of the frictional force between the hemostasis valve  6  and the small diameter part  51  of the hemostasis valve holder  5  is not limited to an intermolecular force. 
     Third Modification 
     With reference to  FIGS.  7  and  8   , the outer needle hub  4  and a hemostasis valve holder  15  according to a third modification, which is a modification of the first embodiment, will be described. Since the hemostasis valve  6  and other components of the indwelling needle are similar to those of the above-described embodiment, the detailed description thereof will be omitted. The same reference numerals are used for the same components as those of the first embodiment. 
       FIG.  7 (A)  is a side view of the outer needle hub  4  to which the hemostasis valve holder  15  is mounted, and  FIG.  7 (B)  is an end view of the outer needle hub  4  to which the hemostasis valve holder  15  is mounted as viewed from the proximal end side along the axis L 1  direction.  FIG.  7 (C)  is a cross-sectional view taken along a direction A-A of the outer needle hub  4  to which the hemostasis valve holder  15  is mounted, and  FIG.  7 (D)  is a cross-sectional view taken along a direction B-B of the outer needle hub  4  to which the hemostasis valve holder  15  is mounted.  FIG.  8    is a side view of the hemostasis valve holder  15 . 
     As illustrated in  FIG.  8   , the hemostasis valve holder  15  includes the small diameter part  51 , the diameter expanded part  52 , and the large diameter part  53  similarly to the first embodiment. In the third modification, as illustrated in  FIGS.  7 (C) and  7 (D) , a flange-shaped end part  151  protruding to the outer diameter side, and an outer insertion part  152  having a substantially cylindrical shape, extending from an edge on the outer diameter side of the end part  151  toward the distal end side so as to cover the outer peripheral side of the large diameter part  53  in parallel with the large diameter part  53  are provided on the rear end side of the large diameter part  53 . The outer insertion part  152  is provided with a claw  153   a  and a claw  153   b  at symmetrical positions with respect to the axis L 1 . The substantially rectangular claws  153   a  and  153   b  are joined to the outer insertion part  152  on the rear end side, and are provided to be elastically deformable in the radial direction with the rear end side as a fulcrum. Provided on the inner diameter side of the claw  153   a  and the claw  153   b  are a protrusion  154   a  and a protrusion  154   b  having a triangular cross section, including an inclined surface  1541   a  and an inclined surface  1541   b  protruding to the inner diameter side from the distal end side toward the rear end side, and an end surface  1542   a  and an end surface  1542   b  on the rear end side perpendicular to the axis L 1  direction. 
     As illustrated in  FIGS.  7 (A) and  7 (D) , the opening  42   a  and the opening  42   b  having a rectangular shape are provided on the rear end side of the main body  40  of the outer needle hub  4 , similarly to the embodiment. A cylindrical gap  155  is formed between the outer insertion part  152  and the large diameter part  53  of the hemostasis valve holder  15 . When the small diameter part  51  of the hemostasis valve holder  15  is press-fitted into the opening at the rear end of the outer needle hub  4 , the main body  40  of the outer needle hub  4  is fitted to the gap  155  from the rear end side. At this time, the inclined surface  1541   a  and the inclined surface  1541   b  abut on the main body  40  of the outer needle hub  4 , so that the claw  153   a  and the claw  153   b  are elastically deformed to the outer diameter side, and the protrusion  154   a  and the protrusion  154   b  rub on an outer surface of the main body  40  of the outer needle hub  4 . When the protrusion  154   a  and the protrusion  154   b  reach the positions of the opening  42   a  and the opening  42   b , the protrusion  154   a  and the protrusion  154   b  are fitted to the opening  42   a  and the opening  42   b , respectively, by elastic return of the claw  153   a  and the claw  153   b.    
     As described above, the protrusion  154   a  and the protrusion  154   b  of the hemostasis valve holder  15  are fitted to the opening  42   a  and the opening  42   b  of the outer needle hub  4  from the outer diameter side, so that the direction around the axis L 1  of the hemostasis valve holder  15  can be guided in a certain direction. Therefore, the direction around the axis L 1  of the hemostasis valve  6  attached to the hemostasis valve holder  15  can be defined. Consequently, blood flowing into the outer needle hub  4  from the outer needle  3  can be smoothly moved to the branch part  41 , and stagnation in the vicinity of the hemostasis valve  6  can be prevented. 
     Here, the opening  42   a  and the opening  42   b  of the outer needle hub  4  constitute the guiding part. The protrusion  154   a  and the protrusion  154   b  constitute the guided part, and the opening  42   a  and the opening  42   b  of the outer needle hub  4  and the protrusion  154   a  and the protrusion  154   b  of the hemostasis valve holder  15  constitute the rotation preventing mechanism. 
     In addition, the protrusion  154   a  and the protrusion  154   b  of the hemostasis valve holder  15  are fitted to the opening  42   a  and the opening  42   b  of the outer needle hub  4  to constitute the locking part that restricts the relative movement in the axis L 1  direction with respect to the outer needle hub  4 . Note that the opening  42   a  and the opening  42   b  may be recesses formed on the outer surface of the outer needle hub  4 . 
     In the third modification, the outer needle hub  4  is provided with the opening  42   a  and the opening  42   b , and the hemostasis valve holder  15  is provided with the protrusion  154   a  and the protrusion  154   b . However, the outer needle hub  4  may be provided with a protrusion, and the hemostasis valve holder  15  may be provided with an opening. The protrusion of the outer needle hub  4  and the opening of the hemostasis valve holder  15  are fitted together, so that the direction around the axis L 1  of the hemostasis valve holder  15  can be guided in a certain direction. Therefore, the direction around the axis L 1  of the hemostasis valve  6  attached to the hemostasis valve holder  15  can be defined. Consequently, blood flowing into the outer needle hub  4  from the outer needle  3  can be smoothly moved to the branch part  41 , and stagnation in the vicinity of the hemostasis valve  6  can be prevented. 
     Fourth Modification 
     With reference to  FIGS.  9  and  10   , the outer needle hub  4  and a hemostasis valve holder  25  according to a fourth modification will be described. Since the hemostasis valve  6  and other components of the indwelling needle are similar to those of the above-described embodiment, the detailed description thereof will be omitted. The same reference numerals are used for the same components as those of the above-described embodiment. 
       FIG.  9 (A)  is a side view of the outer needle hub  4  to which the hemostasis valve holder  25  is mounted, and  FIG.  9 (B)  is an end view of the outer needle hub  4  to which the hemostasis valve holder  25  is mounted as viewed from the proximal end side along the axis L 1 .  FIG.  9 (C)  is a cross-sectional view taken along a direction A-A of the outer needle hub  4  to which the hemostasis valve holder  25  is mounted, and  FIG.  9 (D)  is a cross-sectional view taken along a direction B-B of the outer needle hub  4  to which the hemostasis valve holder  25  is mounted.  FIG.  10 (A)  is a side view of the hemostasis valve holder  25 , and  FIG.  10 (B)  is an end view of the hemostasis valve holder  25  as viewed from the proximal end side. 
     As illustrated in  FIG.  10 (A) , the hemostasis valve holder  25  includes the small diameter part  51  and the diameter expanded part  52  similarly to the first embodiment. In the fourth modification, as illustrated in  FIG.  10 (A) , a claw  251   a  and a claw  251   b  are provided at symmetrical positions with respect to the axis L 1  on the rear end side of the diameter expanded part  52 . The claw  251   a  and the claw  251   b  extend in the axis L 1  direction from a rear end part of the diameter expanded part  52 . The claw  251   a  and the claw  251   b  have a base part  2511   a  and a base part  2511   b  connected to the rear end part of the diameter expanded part  52  and having a partially cylindrical shape conforming to the shape of the rear end part, and a protrusion  2512   a  and a protrusion  2512   b  protruding to the outer diameter side on the rear end side of the base part  2511   a  and the base part  2511   b , respectively. The protrusion  2512   a  forms a triangular cross-sectional shape having an inclined surface  25121   a  protruding to the outer diameter side from the distal end side toward the rear end side, and an end surface  25122   a  connected to the rear end side of the inclined surface  25121   a  and extending in the direction perpendicular to the axis L 1  direction. Similarly, the protrusion  2512   b  forms a triangular cross-sectional shape having an inclined surface  25121   b  and an end surface  25122   b . In the hemostasis valve holder  25 , a partial cylindrical part  252   a  and a partial cylindrical part  252   b  are provided at symmetrical positions with respect to the axis L 1 . The partial cylindrical part  252   a  and the partial cylindrical part  252   b  are circumferentially sandwiched between the claws  251   a  and  251   b  and are connected to the rear end part of the diameter expanded part  52 , conforming to the shape of the rear end part. A gap is formed between each of the claw  251   a  and the claw  251   b  and each of the partial cylindrical part  252   a  and the partial cylindrical part  252   b  in the circumferential direction. 
     As illustrated in  FIGS.  9 (A) and  9 (D) , the opening  42   a  and the opening  42   b  having a rectangular shape are provided on the rear end side of the main body  40  of the outer needle hub  4 , similarly to the embodiment. When the small diameter part  51  of the hemostasis valve holder  25  is press-fitted into the opening at the rear end of the outer needle hub  4 , the rear end part of the outer needle hub  4  rubs on the inclined surface  25121   a  of the protrusion  2512   a  and the inclined surface  25121   b  of the protrusion  2512   b  provided on the claw  251   a  and the claw  251   b , and the apexes of the protrusion  2512   a  and the protrusion  2512   b  abut on the inner peripheral surface of the outer needle hub  4 . Therefore, the claw  251   a  and the claw  251   b  are pressed to the inner diameter side and are elastically deformed to the inner diameter side with the base parts as a fulcrum. When the hemostasis valve holder  25  is further pushed into the outer needle hub  4  toward the distal end side and the protrusion  2512   a  and the protrusion  2512   b  reach the positions of the opening  42   a  and the opening  42   b  of the outer needle hub  4 , the protrusion  2512   a  and the protrusion  2512   b  are fitted to the opening  42   a  and the opening  42   b , respectively, from the inner diameter side by elastic return of the claw  251   a  and the claw  251   b.    
     As described above, the protrusion  2512   a  and the protrusion  2512   b  of the hemostasis valve holder  25  are fitted to the opening  42   a  and the opening  42   b  of the outer needle hub  4  from the inner diameter side, so that the direction around the axis L 1  of the hemostasis valve holder  25  can be guided in a certain direction. Therefore, the direction around the axis L 1  of the hemostasis valve  6  attached to the hemostasis valve holder  25  can be defined. Consequently, blood flowing into the outer needle hub  4  from the outer needle  3  can be smoothly moved to the branch part  41 , and stagnation in the vicinity of the hemostasis valve  6  can be prevented. 
     Here, the opening  42   a  and the opening  42   b  of the outer needle hub  4  constitute the guiding part. The protrusion  2512   a  and the protrusion  2512   b  constitute the guided part, and the opening  42   a  and the opening  42   b  of the outer needle hub  4  and the protrusion  2512   a  and the protrusion  2512   b  of the hemostasis valve holder  25  constitute the rotation preventing mechanism. 
     In addition, the protrusion  2512   a  and the protrusion  2512   b  of the hemostasis valve holder  25  are fitted to the opening  42   a  and the opening  42   b  of the outer needle hub  4  to constitute the locking part that restricts the relative movement in the axis L 1  direction with respect to the outer needle hub  4 . 
     In the fourth modification, the protrusion  2512   a  and the protrusion  2512   b  are provided on the claw  251   a  and the claw  251   b  provided at symmetrical positions with respect to the axis L 1 . Instead, a large diameter part having a cylindrical shape may be provided on the rear end side of the diameter expanded part  52  of the hemostasis valve holder  25 , and a flange having a triangular cross-sectional shape protruding in the outer diameter direction over the entire circumference may be provided on an outer peripheral surface of the large diameter part. In this case, a part of the flange is fitted to each of the opening  42   a  and the opening  42   b  of the outer needle hub  4 . 
     Second Embodiment 
     Hereinafter, an indwelling needle according to a second embodiment of the present invention will be described. The same reference numerals are used for the same components as those of the first embodiment, and the detailed description thereof will be omitted. 
       FIG.  11    is an exploded perspective view of an outer needle hub  34 , a hemostasis valve holder  35 , and the hemostasis valve  6  according to the second embodiment.  FIG.  12 (A)  is a side view illustrating a state in which the hemostasis valve  6  and the hemostasis valve holder  35  are mounted to the outer needle hub  34  according to the second embodiment, and  FIG.  12 (B)  is an end view of the outer needle hub  34  to which the hemostasis valve  6  and the hemostasis valve holder  35  are mounted as viewed from the proximal end side along the axis L 1  direction.  FIG.  12 (C)  is a cross-sectional view taken along a direction C-C of the outer needle hub  34  to which the hemostasis valve  6  and the hemostasis valve holder  35  are mounted, and  FIG.  12 (D)  is a cross-sectional view taken along a direction D-D of the outer needle hub  34  to which the hemostasis valve  6  and the hemostasis valve holder  35  are mounted.  FIG.  12 (E)  is a cross-sectional view taken along a direction A-A of the outer needle hub  34  to which the hemostasis valve  6  and the hemostasis valve holder  35  are mounted. 
     As illustrated in  FIG.  11   , an opening  342   a  and an opening  342   b  having a substantially rectangular shape are opened on the rear end side of the main body  40  of the outer needle hub  34  according to the second embodiment. The opening  342   a  and the opening  342   b  are provided at symmetrical positions with respect to the axis L 1 . In addition, a substantially rectangular parallelepiped protrusion  343  is provided that protrudes in the axis L 1  direction from an end surface  407  on the rear end side of the main body  40  of the outer needle hub  34 . The protrusion  343  is provided between the opening  342   a  and the opening  342   b , and is provided at a position on the side where the branch part  41  branches with respect to the axis L 1 . Substantially rectangular claws  344   a  and  344   b  are provided so as to be elastically deformable in the opening  342   a  and the opening  342   b  of the outer needle hub  34 , respectively. The claw  344   a  and the claw  344   b  are formed in a shape in which the distal end side is bent toward the inner diameter side, and are connected to the main body  40  on the rear end side. 
     As illustrated in  FIGS.  12 (C) and  12 (D) , a hollow portion  3405  is provided on the rear end side of the hollow portion  400  inside the outer needle hub  34 . The inner diameter of the hollow portion  3405  is substantially constant in the axis L 1  direction. A hollow portion  3407  having an inner diameter larger than that of the hollow portion  3405  is provided on the rear end side of the hollow portion  3405  via a hollow portion  3406  having a diameter increasing to the outer diameter side. The opening  342   a  and the opening  342   b  are opened so as to penetrate the outer needle hub  34  in the outer diameter direction from the hollow portion  3406  to the hollow portion  3407 . 
     As illustrated in  FIG.  11   , in the hemostasis valve holder  35  according to the second embodiment, a cylindrical medium diameter part  352  having a diameter larger than that of the small diameter part  51  and having a constant diameter in the axis L 1  direction is connected to the rear end side of the small diameter part  51  similar to that in the first embodiment via an end surface  352   a  extending in the direction perpendicular to the axis L 1  direction. A cylindrical second medium diameter part  354  having substantially the same diameter as that of the medium diameter part  352  is connected to the rear end side of the medium diameter part  352  via a flange part  353  having, over the entire circumference, a first diameter expanded part  3531  having a diameter increasing toward the rear end side and an end surface  3532  extending in the direction perpendicular to the axis L 1  direction. On the rear end side of the second medium diameter part  354 , a second diameter expanded part  355  having a diameter increasing toward the rear end side is provided over the entire circumference. A cylindrical large diameter part  356  having a diameter larger than those of the medium diameter part  352  and the second medium diameter part  354 , and having a diameter substantially equal to that of the flange part  353  is provided continuously from the second diameter expanded part  355 . An annular flange part  357  protruding to the outer diameter side is formed at a rear end part of the large diameter part  356 . Provided on the distal end side of the flange part  357  is a recess  3571  that is recessed from a part of an end surface  357   a  on the distal end side toward the rear end side. The recess  3571  opens from the end surface  357   a  on the distal end side of the flange part  357  to an outer peripheral surface  357   b . The recess  3571  is provided at a position opposite to the side where the inclined first end surface  51   a  of the small diameter part  51  protrudes to the distal end side with respect to the axis L 1 . 
     The hemostasis valve holder  35  to which the hemostasis valve  6  is attached is press-fitted from the opening at the rear end of the outer needle hub  34  to be attached to the outer needle hub  34 . When the hemostasis valve holder  35  is press-fitted into the outer needle hub  34 , distal end parts  3441   a  and  3441   b  of the claws  344   a  and  344   b  are pressed to the outer diameter side and elastically deformed by abutting on the first diameter expanded part  3531  of the flange part  353  of the hemostasis valve holder  35 . When the hemostasis valve holder  35  is further pushed into the outer needle hub  34  toward the distal end side, the distal end parts  3441   a  and  3441   b  of the claws  344   a  and  344   b  rub on the first diameter expanded part  3531  of the flange part  353  of the hemostasis valve holder  35 . When the hemostasis valve holder  35  is appropriately positioned in the outer needle hub  34 , the distal end parts  3441   a  and  3441   b  of the claws  344   a  and  344   b  climb over the first diameter expanded part  3531  of the flange part  353  of the hemostasis valve holder  35 . As illustrated in  FIG.  12 (D) , since the second medium diameter part  354  is provided on the rear end side of the flange part  353  in contact with the end surface  3532 , the claw  344   a  and the claw  344   b  pressed to the outer diameter side elastically return to the inner diameter side, and the distal end part  3441   a  and the distal end part  3441   b  come into abutment with the second medium diameter part  354 . At this time, parts of the claws  344   a  and  344   b  closer to the rear end than the distal end parts  3441   a  and  3441   b  may abut on the second diameter expanded part  355 . The first diameter expanded part  3531  of the flange part  353  of the hemostasis valve holder  35  faces and abuts on an inner peripheral surface of the hollow portion  3406  of the outer needle hub  34  inside a part circumferentially sandwiched between the opening  342   a  and the opening  342   b  of the outer needle hub  34 . At this time, the large diameter part  356  of the hemostasis valve holder  35  faces and abuts on the hollow portion  3407  of the outer needle hub  34 . In addition, when the hemostasis valve holder  35  is appropriately positioned in the outer needle hub  34 , the protrusion  343  of the outer needle hub is fitted to the recess  3571  of the flange part  357  of the hemostasis valve holder  35 . 
     As described above, the claw  344   a  and the claw  344   b  of the outer needle hub  34  are fitted to a recess formed by the flange part  353 , the second medium diameter part  354 , and the second diameter expanded part  355  of the hemostasis valve holder  35 , and the protrusion  343  of the outer needle hub  34  is fitted to the recess  3571  in the axis L 1  direction, so that the direction around the axis L 1  of the hemostasis valve holder  35  can be guided in a certain direction. Therefore, the direction around the axis L 1  of the hemostasis valve  6  attached to the hemostasis valve holder  35  can be defined. Consequently, blood flowing into the outer needle hub  34  from the outer needle  3  can be smoothly moved to the branch part  41 , and stagnation in the vicinity of the hemostasis valve  6  can be prevented. 
     Here, the claw  344   a  and the claw  344   b  of the outer needle hub  34  and the flange part  353  of the hemostasis valve holder  35  define relative positions of the hemostasis valve and the hemostasis valve holder in the axis direction with respect to the outer needle hub. The protrusion  343  and the recess  3571  define relative positions of the hemostasis valve and the hemostasis valve holder in the direction around the axis with respect to the outer needle hub. That is, the protrusion  343  constitutes the guiding part and constitutes the locking part, the recess  3571  constitutes the guided part, and both of them constitute the rotation preventing mechanism. 
     Fifth Modification 
     With reference to  FIGS.  13 (A) to  13 (D) , an outer needle hub  74  and a hemostasis valve holder  75  according to a fifth modification, which is a modification of the second embodiment, will be described. Since the hemostasis valve  6  and other components of the indwelling needle are similar to those of the above-described embodiments, the detailed description thereof will be omitted. The same reference numerals are used for the same components as those of the first and second embodiments.  FIG.  13 (A)  is a plan view illustrating a state in which the hemostasis valve  6  and the hemostasis valve holder  75  are mounted to the outer needle hub  74  according to the fifth modification, and  FIG.  13 (B)  is a cross-sectional view taken along a direction A-A of the outer needle hub  74  to which the hemostasis valve  6  and the hemostasis valve holder  75  are mounted.  FIG.  13 (C)  is a side view illustrating a state in which the hemostasis valve  6  and the hemostasis valve holder  75  are mounted to the outer needle hub  74  in the indwelling needle according to the fifth modification, and  FIG.  13 (D)  is a cross-sectional view taken along a direction B-B of the outer needle hub  74  to which the hemostasis valve  6  and the hemostasis valve holder  75  are mounted. 
     As illustrated in  FIGS.  13 (B) and  13 (D) , in the fifth modification, no flange part is provided on the rear end side of a large diameter part  756  of the hemostasis valve holder  75 , and the large diameter part  756  is provided up to the rear end. In addition, although the outer needle hub  74  according to the fifth modification has substantially the same configuration as that of the second embodiment, the rear end side of the main body  40  is extended along the axis L 1  direction. The main body  40  extends to the rear end side beyond the rear end of the appropriately positioned hemostasis valve holder  75 . Furthermore, in the fifth modification, the outer needle hub  74  is not provided with the protrusion  343 . 
     Note that the configuration of the hemostasis valve  6  according to the fifth modification is similar to that of the first embodiment and the second embodiment. 
     As described above, the claws  344   a  and  344   b  of the outer needle hub  74  are fitted to the recess formed by the flange part  353 , the second medium diameter part  354 , and the second diameter expanded part  355  of the hemostasis valve holder  75 , so that axial positions of the hemostasis valve  6  and the hemostasis valve holder  75  can be defined. In addition, the hemostasis valve  6  and a peripheral wall part of the outer needle hub  74  can guide the direction around the axis L 1  of the hemostasis valve holder  75  in a certain direction. 
     Sixth Modification 
     With reference to  FIGS.  14  and  15   , an outer needle hub  84  and a hemostasis valve holder  85  according to a sixth modification, which is a modification of the second embodiment, will be described. Since the hemostasis valve  6  and other components of the indwelling needle are similar to those of the above-described embodiment, the detailed description thereof will be omitted. The same reference numerals are used for the same components as those of the above-described embodiment. 
       FIG.  14 (A)  is a side view of the outer needle hub  84  to which the hemostasis valve holder  85  is mounted, and  FIG.  14 (B)  is an end view of the outer needle hub  84  to which the hemostasis valve holder  85  is mounted as viewed from the proximal end side along the axis L 1 .  FIG.  14 (C)  is a cross-sectional view taken along a direction A-A of the outer needle hub  84  to which the hemostasis valve holder  85  is mounted, and  FIG.  14 (D)  is a cross-sectional view taken along a direction B-B of the outer needle hub  84  to which the hemostasis valve holder  85  is mounted.  FIG.  15 (A)  is a side view of the hemostasis valve holder  85 , and  FIG.  15 (B)  is an end view of the hemostasis valve holder  85  as viewed from the proximal end side. 
     As illustrated in  FIGS.  14 (A) and  14 (D) , similarly to the second embodiment, the opening  342   a  and the opening  342   b  having a substantially rectangular shape are opened in the outer needle hub  84  according to the sixth modification, and the substantially rectangular claws  344   a  and  344   b  are provided so as to be elastically deformable in the opening  342   a  and the opening  342   b , respectively. Note that the outer needle hub  84  according to the sixth modification is not provided with the protrusion  343 . 
     As illustrated in  FIG.  15 (A) , the hemostasis valve holder  85  is provided with the cylindrical medium diameter part  352  on the rear end side of the small diameter part  51 , a diameter expanded part  853  having a diameter increasing toward the rear end side, a large diameter part  854 , and a flange part  856  protruding to the outer diameter side. A recess  855   a  and a recess  855   b  are provided adjacent to the diameter expanded part  853  on the distal end side of the large diameter part  854 . The recess  855   a  has, on the distal end side, an end surface  8551   a  extending from an outer surface of the large diameter part  854  to the inner diameter side, a bottom part  8552   a  provided continuously from an end part on the inner diameter side of the end surface  8551   a , a side surface  8553   a  and a side surface  8554   a  provided continuously from circumferential opposite end parts of the end surface  8551   a , and an inclined surface part  8555   a  inclined to the outer diameter side from the bottom part  8552   a  toward the rear end side and provided continuously from the outer surface of the large diameter part. Similarly, the recess  855   b  has an end surface  8551   b , a bottom part  8552   b , a side surface  8553   b , a side surface  8554   b , and an inclined surface part  8555   b . The recess  855   a  and the recess  855   b  are provided at symmetrical positions with respect to the axis L 1 . 
     When the small diameter part  51  of the hemostasis valve holder  85  is press-fitted into the opening on the rear end side of the outer needle hub  84 , the distal end parts  3441   a  and  3441   b  of the claws  344   a  and  344   b  of the outer needle hub  84  are pressed to the outer diameter side and elastically deformed by the diameter expanded part  853  of the hemostasis valve holder  85 . When the hemostasis valve holder  85  is further pushed toward the distal end side of the outer needle hub  84  and the claw  344   a  and the claw  344   b  reach the recess  855   a  and the recess  855   b , respectively, the claw  344   a  and the claw  344   b  elastically return to bend to the inner diameter side, and the distal end parts  3441   a  and  3441   b  of the claws  344   a  and  344   b  come into abutment with the bottom parts  8552   a  and  8552   b . As a result, the claw  344   a  and the claw  344   b  of the outer needle hub  84  are fitted to the recess  855   a  and the recess  855   b  of the hemostasis valve holder  85 . 
     As described above, the claw  344   a  and the claw  344   b  of the outer needle hub  84  are fitted to the recess  855   a  and the recess  855   b  of the hemostasis valve holder  85 , so that the direction around the axis L 1  of the hemostasis valve holder  85  can be guided in a certain direction. Therefore, the direction around the axis L 1  of the hemostasis valve  6  attached to the hemostasis valve holder  85  can be defined. Consequently, blood flowing into the outer needle hub  84  from the outer needle  3  can be smoothly moved to the branch part  41 , and stagnation in the vicinity of the hemostasis valve  6  can be prevented. 
     Here, the claw  344   a  and the claw  344   b  of the outer needle hub  84  constitute the guiding part. The recess  855   a  and the recess  855   b  constitute the guided part, and the claw  344   a  and the claw  344   b  of the outer needle hub  84  and the recess  855   a  and the recess  855   b  of the hemostasis valve holder  85  constitute the rotation preventing mechanism. 
     In addition, the recess  855   a  and the recess  855   b  of the hemostasis valve holder  85  are fitted to the claw  344   a  and the claw  344   b  of the outer needle hub  84  to constitute the locking part that restricts the relative movement in the axis L 1  direction with respect to the outer needle hub  84 . 
     Seventh Modification 
     Hereinafter, a seventh modification, which is a modification of the first embodiment and the second embodiment, will be described. The same reference numerals are used for the same components as those of the first and second embodiments, and the detailed description thereof will be omitted. 
       FIG.  16    is a plan view of an outer needle hub  94  to which the hemostasis valve  6  is attached according to the seventh modification.  FIG.  17    is a cross-sectional view taken along a direction C-C of the outer needle hub  94  to which the hemostasis valve  6  is attached according to the seventh modification. 
     Only the hemostasis valve  6  may be first attached to the outer needle hub  94  as illustrated in  FIG.  17   , without attaching the hemostasis valve holder  5  to which the hemostasis valve  6  is attached, to the outer needle hub  4  as described in the first and second embodiments. In this case, as illustrated in  FIGS.  18 (A) to  18 (C) , the hemostasis valve  6  can be provided with the rotation preventing mechanism.  FIGS.  18 (A) to  18 (C)  illustrate the hemostasis valve  6  and the outer needle hub  94  in an E-E cross section of  FIG.  17   . In this manner, the hemostasis valve  6  can be attached to the outer needle hub  94 , and then the hemostasis valve holder  5  can be press-fitted into and mounted to the outer needle hub  94 . Alternatively, the hemostasis valve  6  may be made thick without providing the hemostasis valve holder  5 . 
     In  FIG.  18 (A) , ribs  60   a ,  60   b , and  60   c  in the axis L 1  direction are provided at three positions in the circumferential direction of the cylindrical part  60  of the hemostasis valve  6 , and grooves  405   a ,  405   b , and  405   c  in the axis L 1  direction are provided at positions corresponding to the ribs  60   a ,  60   b , and  60   c  on the inner peripheral surface of the hollow portion  405  of the main body  40  of the outer needle hub  94 . When the hemostasis valve  6  is press-fitted into the hollow portion  405  of the main body  40  of the outer needle hub  94 , the hemostasis valve  6  can be attached to the outer needle hub  94  without rotating the hemostasis valve  6  about the axis L 1  by moving the hemostasis valve  6  in the axis L 1  direction while fitting the ribs  60   a ,  60   b , and  60   c  of the hemostasis valve  6  to the grooves  405   a ,  405   b , and  405   c  on the inner peripheral surface of the hollow portion  405 , respectively. That is, the grooves  405   a ,  405   b , and  405   c  on the inner peripheral surface of the hollow portion  405  of the outer needle hub  94  can guide the direction around the axis L 1  of the hemostasis valve  6  in a certain direction. Therefore, the direction around the axis L 1  of the hemostasis valve  6  can be defined. Consequently, blood flowing into the outer needle hub  94  from the outer needle  3  can be smoothly moved to the branch part  41 , and stagnation in the vicinity of the hemostasis valve  6  can be prevented. Here, the grooves  405   a ,  405   b , and  405   c  on the inner peripheral surface of the hollow portion  405  of the outer needle hub  94  constitute the guiding part. The ribs  60   a ,  60   b , and  60   c  of the hemostasis valve  6  constitute the guided part, and the ribs  60   a ,  60   b , and  60   c  and the grooves  405   a ,  405   b , and  405   c  on the inner peripheral surface of the hollow portion  405  constitute the rotation preventing mechanism. Note that the positions of the ribs  60   a ,  60   b , and  60   c  of the hemostasis valve  6  are not limited to the case of being arranged at equal intervals in the circumferential direction of the cylindrical part  60 , and may be arranged at different intervals in the circumferential direction of the cylindrical part  60 . In this case, the grooves  405   a ,  405   b , and  405   c  on the inner peripheral surface of the main body  40  of the outer needle hub  94  are also provided at positions corresponding to the ribs  60   a ,  60   b , and  60   c  of the hemostasis valve  6 . In addition, the guiding part may extend to the proximal end of the outer needle hub  94 . 
     In  FIG.  18 (B) , grooves  60   d ,  60   e , and  60   f  in the axis L 1  direction are provided at three positions in the circumferential direction of the cylindrical part  60  of the hemostasis valve  6 , and ribs  405   d ,  405   e , and  405   f  in the axis L 1  direction are provided at positions corresponding to the grooves  60   d ,  60   e , and  60   f  on the inner peripheral surface of the hollow portion  405  of the main body  40  of the outer needle hub  94 . When the hemostasis valve  6  is press-fitted into the hollow portion  405  of the main body  40  of the outer needle hub  94 , the hemostasis valve  6  can be attached to the outer needle hub  94  without rotating the hemostasis valve  6  about the axis L 1  by moving the hemostasis valve  6  in the axis L 1  direction while fitting the grooves  60   d ,  60   e , and  60   f  of the hemostasis valve  6  to the ribs  405   d ,  405   e , and  405   f  on the inner peripheral surface of the hollow portion  405 , respectively. That is, the ribs  405   d ,  405   e , and  405   f  on the inner peripheral surface of the hollow portion  405  of the outer needle hub  94  can guide the direction around the axis L 1  of the hemostasis valve  6  in a certain direction. Therefore, the direction around the axis L 1  of the hemostasis valve  6  can be defined. Consequently, blood flowing into the outer needle hub  94  from the outer needle  3  can be smoothly moved to the branch part  41 , and stagnation in the vicinity of the hemostasis valve  6  can be prevented. Here, the ribs  405   d ,  405   e , and  405   f  on the inner peripheral surface of the hollow portion  405  of the outer needle hub  94  constitute the guiding part. The grooves  60   d ,  60   e , and  60   f  of the hemostasis valve  6  constitute the guided part, and the grooves  60   d ,  60   e , and  60   f  and the ribs  405   d ,  405   e , and  405   f  on the inner peripheral surface of the hollow portion  405  constitute the rotation preventing mechanism. Note that the positions of the grooves  60   d ,  60   e , and  60   f  of the hemostasis valve  6  are not limited to the case of being arranged at equal intervals in the circumferential direction of the cylindrical part  60 , and may be arranged at different intervals in the circumferential direction of the cylindrical part  60 . In this case, the ribs  405   d ,  405   e , and  405   f  on the inner peripheral surface of the main body  40  of the outer needle hub  94  are also provided at positions corresponding to the grooves  60   d ,  60   e , and  60   f  of the hemostasis valve  6 . In addition, the guiding part may extend to the proximal end of the outer needle hub  94 . 
     In  FIG.  18 (C) , the cylindrical part  60  of the hemostasis valve  6  has a triangular tube shape with rounded corners, and the hollow portion  405  of the main body  40  of the outer needle hub  94  has a triangular prism shape with rounded corners. The hemostasis valve  6  having such a shape is configured such that a portion where a distance from the axis L 1  to an outer peripheral surface of the cylindrical part  60  is long and a portion where the distance is short appear at different positions in the circumferential direction. When the hemostasis valve  6  is press-fitted into the hollow portion  405  of the main body  40  of the outer needle hub  94 , the hemostasis valve  6  can be attached to the outer needle hub  94  without rotating the hemostasis valve  6  about the axis L 1  by moving the hemostasis valve  6  in the axis L 1  direction while matching the outer shape of the cylindrical part  60  of the hemostasis valve  6  with the inner peripheral shape of the hollow portion  405 . That is, the inner peripheral shape of the hollow portion  405  of the outer needle hub  94  can guide the direction around the axis L 1  of the hemostasis valve  6  in a certain direction. Therefore, the direction around the axis L 1  of the hemostasis valve  6  can be defined. Consequently, blood flowing into the outer needle hub  94  from the outer needle  3  can be smoothly moved to the branch part  41 , and stagnation in the vicinity of the hemostasis valve  6  can be prevented. Here, the inner peripheral shape of the hollow portion  405  constitutes the guiding part. The outer shape of the cylindrical part  60  of the hemostasis valve  6  constitutes the guided part, and the outer shape of the cylindrical part  60  and the inner peripheral shape of the hollow portion  405  constitute the rotation preventing mechanism. Note that the shape of the cylindrical part  60  of the hemostasis valve  6  is not limited to the above-described shape, and may be a shape in which the portions with a long distance and a short distance from the axis L 1  to the outer peripheral surface of the cylindrical part  60  appear at unequal intervals in the circumferential direction, or may be a shape in which the length of the distance from the axis L 1  to the outer peripheral surface of the cylindrical part  60  is different in the circumferential direction. Note that the guided part illustrated in  FIGS.  18 (A) to  18 (C)  may be provided in the hemostasis valve holder. 
     Eighth Modification 
     Hereinafter, an eighth modification, which is a modification of the first embodiment and the second embodiment, will be described. The same reference numerals are used for the same components as those of the first and second embodiments, and the detailed description thereof will be omitted. 
       FIG.  19    is an exploded perspective view of an outer needle hub  104 , the hemostasis valve  6 , and a hemostasis valve holder  105  according to the eighth modification. 
     As illustrated in  FIG.  19   , an indication  45  for alignment of a relative positional relationship in the rotation direction about the axis L 1  is given to an outer peripheral surface on the rear end side of the main body  40  of the outer needle hub  104 . An indication for alignment of the relative positional relationship in the rotation direction about the axis L 1  is also given to corresponding positions on outer peripheral surfaces of the diameter expanded part  52  and the large diameter part  53  of the hemostasis valve holder  105 . To align the direction of the indication  45  of the outer needle hub  104  and the direction of an indication  57  of the hemostasis valve holder  105  with each other when attaching the hemostasis valve holder  105 , to which the hemostasis valve  6  is attached, to the outer needle hub  104 , the hemostasis valve holder  105  is press-fitted from the opening on the rear end side of the outer needle hub  104  while maintaining the posture of the hemostasis valve holder  105  with respect to the outer needle hub  104  by reference to the indications  45  and  57 . This makes it possible to prevent the rotation of the hemostasis valve  6  and the hemostasis valve holder  105  about the axis L 1 . That is, the indication  45  of the outer needle hub  104  can guide the direction around the axis L 1  of the hemostasis valve holder  105  in a certain direction. Therefore, the direction around the axis L 1  of the hemostasis valve  6  can be defined. Consequently, blood flowing into the outer needle hub  104  from the outer needle  3  can be smoothly moved to the branch part  41 , and stagnation in the vicinity of the hemostasis valve  6  can be prevented. Here, the indication  45  of the outer needle hub  104  constitutes the guiding part. The indication  57  of the hemostasis valve holder  105  constitutes the guided part. The indication  45  of the outer needle hub  104  and the indication  57  of the hemostasis valve holder  105  constitute the rotation preventing mechanism. The indication for alignment with the indication of the outer needle hub  104  may be given to the outer peripheral surface of the cylindrical part  60  of the hemostasis valve  6 , or may be given to the outer peripheral surfaces of both the hemostasis valve  6  and the hemostasis valve holder  105 . 
     In addition, as the contents of the indications, characters, symbols, figures, and the like can be used, and any form may be employed as long as an operator can recognize the contents. Furthermore, the indications are not limited to being two-dimensionally expressed by printing or the like, and may be three-dimensionally expressed. 
     Third Embodiment 
     Hereinafter, an indwelling needle according to a third embodiment of the present invention will be described. The same reference numerals are used for the same components as those of the first and second embodiments, and the description thereof will be omitted. 
     Since the inner needle  2  and the inner needle hub  21  of the indwelling needle are similar to those of the first embodiment, the description thereof will be omitted. 
     The outer needle hub  34  according to the third embodiment is similar to that of the second embodiment illustrated in  FIG.  11   , whereas a hemostasis valve  16  and a hemostasis valve holder  115  are different from those of the first and second embodiments.  FIG.  20 (A)  illustrates a plan view of the outer needle hub  34  to which the hemostasis valve  16  and the hemostasis valve holder  115  of the third embodiment are mounted, and  FIG.  20 (B)  illustrates an A-A cross-sectional view of the same.  FIG.  21 (A)  illustrates a side view of the outer needle hub  34  to which the hemostasis valve  16  and the hemostasis valve holder  115  of the third embodiment are mounted, and FIG.  21 (B) illustrates a B-B cross-sectional view of the same.  FIG.  22 (A)  illustrates a perspective view of the hemostasis valve  16  of the third embodiment, and  FIG.  22 (B)  illustrates an A-A cross-sectional view of the same.  FIG.  23 (A)  illustrates a side view of the hemostasis valve holder  115  of the third embodiment, and  FIG.  23 (B)  illustrates a side view of a hemostasis valve holder  125  of a reference example.  FIG.  24 (A)  illustrates an A-A cross-sectional view of the outer needle hub  34  to which a hemostasis valve  26  and the hemostasis valve holder  125  of the reference example are mounted, and  FIG.  24 (B)  illustrates a B-B cross-sectional view of the same. 
     As illustrated in  FIG.  22 (A) , the hemostasis valve  16  includes the first end surface  61 , the step part  62 , and the second end surface  63  on the distal end side similarly to the first and second embodiments. A slit  164  of the hemostasis valve  16  is provided in a direction perpendicular to a plane including the axis L 1  and the axis L 2 , and the direction of the slit  64  is perpendicular to the direction of the slit  164  of the hemostasis valve  6  of the first embodiment. Since the central proximal end surface  66  of the hemostasis valve  6  according to the first and second embodiments is formed in parallel with the first end surface  61  and the second end surface  63  to be inclined with respect to the axis L 1  direction, the soft solid part  631  sandwiched between the first end surface  61  and the second end surface  63 , and the central proximal end surface  66  is thin. On the other hand, as illustrated in  FIG.  22 (B) , a central proximal end surface  166  of the hemostasis valve  16  is formed to be perpendicular to the axis L 1  direction instead of being parallel to the first end surface  61  and the second end surface  63 . Therefore, in the hemostasis valve  16 , a soft solid part  1631  sandwiched between the first and second end surfaces  61  and  63  and the central proximal end surface  166  is formed thick. Here, in the first end surface  61  of the hemostasis valve  16 , a part connected to a cylindrical part  160  on the most proximal end side is referred to as an end point  61   a  of the first end surface  61 , and a part at a symmetrical position to the end point of the first end surface  61  with respect to the axis L 1  and connected to the cylindrical part  160  on the most distal end side is referred to as a starting point  61   b  of the first end surface  61 . In the hemostasis valve  16 , the cylindrical part  160  includes a first cylindrical part  1601  having the solid part  1631  on the inner diameter side, and a second cylindrical part  1602  extending from the first cylindrical part  1601  to the proximal end side along the axis L 1  direction and having a hollow portion on the inner diameter side. Here, the second cylindrical part  1602  corresponds to a cylindrical part of the present invention. In addition, in the hemostasis valve  16 , the length in the axis L 1  direction of a portion of the cylindrical part  160  (here, the portion coincides with the second cylindrical part  1602 ) extending from the end point  61   a  of the first end surface  61  to the proximal end side is set to be longer than the length in the axis L 1  direction of a portion of the cylindrical part  60  according to the first and second embodiments extending from the end point  61   a  of the first end surface  61  to the proximal end side. The portion extending from the end point  61   a  of the first end surface  61  to the proximal end side has a length of 1 mm or more, preferably 2 mm or more, in the axis L 1  direction from the end point  61   a  of the first end surface  61 . In addition, in the second cylindrical part  1602  of the hemostasis valve  16 , a thick part  1602   a  having a large thickness in the radial direction is provided on the proximal end side along the axis L 1  direction with respect to the end point of the first end surface  61 . As the thick part  1602   a , a large diameter part having a rectangular cross section and protruding to the outer diameter side is formed over the entire circumference around the axis L 1 . The thick part  1602   a  is provided on the rear end side of the second cylindrical part  1602 . The outer diameter of the thick part  1602   a  is set to be larger than the inner diameter of a part of the hollow portion  3405  of the outer needle hub  34  facing the thick part  1602   a  when the hemostasis valve  16  is appropriately positioned in the outer needle hub  34 . In addition, the thickness of the thick part  1602   a  in the radial direction is set to be larger than an interval between a small diameter part  1151  of the hemostasis valve holder  115  that supports the second cylindrical part  1602  from the inner diameter side and the inner peripheral surface of the hollow portion  3405  of the outer needle hub  34  facing the small diameter part  1151  via the second cylindrical part  1602  when the hemostasis valve  16  and the hemostasis valve holder  115  are appropriately positioned in the outer needle hub  34 . The cross-sectional shape of the thick part  1602   a  is not limited to the configuration in which the thickness in the axis L 1  direction is constant, and an appropriate shape can be adopted. A region of the second cylindrical part  1602  where the thick part  1602   a  is formed is not limited to a region on the rear end side, and the thick part  1602   a  can be provided in a part or all of an appropriate region of a region from the end point  61   a  of the first end surface  61  to an end surface  165  on the rear end side. In addition, the region of the second cylindrical part  1602  where the thick part  1602   a  is formed is not limited to the entire circumference around the axis L 1 , and the thick part  1602   a  can be provided in a region from the end point  61   a  of the first end surface  61  to the end surface  165  on the rear end side, that is, in a part in the circumferential direction including a region in the direction in which the branch part  41  branches. 
     In accordance with the configuration of the soft solid part  1631  and the central proximal end surface  166  of the hemostasis valve  16  as described above, the small diameter part  1151  of the hemostasis valve holder  115  has a cylindrical shape, and a substantially annular end surface  1151   a  is formed at an end part on the distal end side of the small diameter part  1151  in the direction perpendicular to the axis L 1  direction as illustrated in  FIG.  23 (A) . A protrusion  1151   b  protruding in the axis L 1  direction is formed on the end surface  1151   a . The protrusion  1151   b  is provided on the side opposite to the recess  3571  with respect to the axis L 1 . The shape of the protrusion  1151   b  is not limited, but its distal end part desirably has a rounded shape. The end surface  1151   a  is provided with an annular protrusion  1151   c  protruding in the axis L 1  direction similarly to the protrusion  1151   b . The annular protrusion  1151   c  is formed over the entire circumference on an outer peripheral edge of the end surface  1151   a . In the hemostasis valve holder  115 , the shape of the end part on the distal end side of the small diameter part  1151  is different from that of the hemostasis valve holder  35 , and the length in the axis L 1  direction of the small diameter part  1151  is set to be longer than that of the small diameter part  51  of the hemostasis valve holder  35 . Here, the small diameter part  1151  corresponds to an attachment-target part of the present invention. The hemostasis valve holder  115  is configured similarly to the hemostasis valve holder  35  except that the length in the axis L 1  direction of a large diameter part  1152  on the proximal end side from an end surface  1152   a  provided on the proximal end side of the small diameter part  1151  of the hemostasis valve holder  115  is shorter than that of the hemostasis valve holder  35 . 
     The outer dimension of the small diameter part  1151  of the hemostasis valve holder  115  is set to be slightly smaller than the inner diameter dimension of the cylindrical part  160  of the hemostasis valve  16 . When the small diameter part  51  of the hemostasis valve holder  115  is fitted into the cylindrical part  160  of the hemostasis valve  16  from the distal end side, the cylindrical part  160  of the hemostasis valve  16  slightly increases in diameter to the outer diameter side, but tries to decrease in diameter to be elastically deformed. The elastic deformation produces a frictional force between the inner peripheral surface of the cylindrical part  160  of the hemostasis valve  16  and the outer peripheral surface of the small diameter part  1151  of the hemostasis valve holder  115 . When the hemostasis valve holder  115  is fitted into the hemostasis valve  16  until the end surface  165  on the rear end side of the cylindrical part  160  of the hemostasis valve  16  abuts on the end surface  1151   a  as the distal end surface of the hemostasis valve holder  115 , the end surface  1151   a  of the hemostasis valve holder  115  abuts on the central proximal end surface  166  of the hemostasis valve  16 , and the protrusion  1151   b  of the hemostasis valve holder  115  presses the central proximal end surface  166 . When the hemostasis valve  16  is appropriately mounted to the hemostasis valve holder  115 , the protrusion  1151   b  coincides with a direction around the axis L 1  in which the first end surface  61  and the second end surface  63  of the hemostasis valve  16  are located on the most distal end side. Therefore, when the hemostasis valve  16  is mounted to the hemostasis valve holder  115 , the protrusion  1151   b  functions as a guide in mounting the hemostasis valve  16  in a predetermined direction around the axis L 1 . In addition, since the protrusion  1151   b  presses and slightly deforms the central proximal end surface  166  of the hemostasis valve  16 , the protrusion  1151   b  constitutes the rotation preventing mechanism that restricts the relative rotation about the axis L 1  between the hemostasis valve holder  115  and the hemostasis valve  16 . Furthermore, since the annular protrusion  1151   c  also presses and slightly deforms the central proximal end surface  166  of the hemostasis valve  16 , it is possible to prevent displacement between the hemostasis valve holder  115  and the hemostasis valve  16  and to suppress generation of a gap that causes liquid leakage between the hemostasis valve  16  and the outer needle hub  34 . 
     In addition, as illustrated in  FIG.  22 (B) , the central proximal end surface  166  of the hemostasis valve  16  is located in the vicinity of the proximal end side of the end point  61   a  of the first end surface  61  along the axis L 1  direction, and the end surface  1151   a  of the hemostasis valve holder  115  is fitted up to this position. Therefore, when the hemostasis valve  16  is appropriately attached to the hemostasis valve holder  115 , the small diameter part  1151  of the hemostasis valve holder  115  is arranged on the inner diameter side of the second cylindrical part  1602  of the hemostasis valve  16 , and the second cylindrical part  1602  is supported by the small diameter part  1151  from the inner diameter side. As described above, when the hemostasis valve  16  and the hemostasis valve holder  115  are appropriately positioned in the outer needle hub  34 , the thickness of the thick part  1602   a  in the radial direction is set to be larger than the interval between the small diameter part  1151  of the hemostasis valve holder  115  that supports the second cylindrical part  1602  from the inner diameter side and the inner peripheral surface of the hollow portion  3405  of the outer needle hub  34  facing the small diameter part  1151  via the second cylindrical part  1602 . Therefore, when the hemostasis valve holder  115  to which the hemostasis valve  16  is attached is appropriately positioned with respect to the outer needle hub  34  as illustrated in  FIGS.  20 (B) and  21 (B) , the thick part  1602   a  is compressed between the hemostasis valve holder  115  and the inner peripheral surface of the hollow portion  3405  of the outer needle hub  34 . When the thick part  1602   a  of the hemostasis valve  16  is compressed in the radial direction, the thick part  1602   a  comes into pressure contact with the inner peripheral surface of the hollow portion  3405  of the outer needle hub  34  by an elastic force, so that a gap between the cylindrical part  160  of the hemostasis valve  16  and the hollow portion  3405  of the outer needle hub  34  is sealed. Therefore, even if a gap is generated between the step part  62  and the first end surface  61  of the hemostasis valve  16 , and the opening  404  and the step part  406  of the outer needle hub  34 , and also between the cylindrical part  160  of the hemostasis valve  16  and the inner peripheral surface of the hollow portion  3405  of the outer needle hub  34  due to backlash or displacement of the components, deformation of the hemostasis valve  16 , or the like, it is possible to suppress leakage of a fluid flowing through the hollow portion  400  and the hollow portion  410 , to the proximal end side beyond the thick part  1602   a  of the hemostasis valve  16 . 
       FIG.  23 (B)  illustrates a side view of the hemostasis valve holder  125  of the reference example.  FIG.  24 (A)  is an A-A cross-sectional view (see  FIG.  20 (A) ) illustrating a state in which the hemostasis valve holder  125  to which the hemostasis valve  26  of the reference example is attached is appropriately mounted to the outer needle hub  34 , and  FIG.  24 (B)  is a B-B cross-sectional view of the same (see  FIG.  21 (A) ). The same reference numerals are used for the same components as those of the first to third embodiments. 
     Similarly to the hemostasis valve  16 , a central proximal end surface  266  of the hemostasis valve  26  is formed in the direction perpendicular to the axis L 1  direction, and an end surface  1251   a  on the distal end side of a small diameter part  1251  of the hemostasis valve holder  125  is also correspondingly formed in the direction perpendicular to the axis L 1  direction. In addition, a protrusion  1251   b  protruding in the axis L 1  direction is formed on the end surface  1251   a  of the hemostasis valve holder  125 . The shape and function of the protrusion  1251   b  are similar to those of the protrusion  1151   b . In the hemostasis valve  26 , the length in the axis direction of a first cylindrical part  2601  of a cylindrical part  260  is the same as the length in the axis L 1  direction of the first cylindrical part  1601  of the hemostasis valve  16 , whereas the length in the axis L 1  direction of a second cylindrical part  2602  is set to be shorter than the length in the axis L 1  direction of the second cylindrical part  1602  of the hemostasis valve  16 . Correspondingly, the length in the axis L 1  direction of the small diameter part  1251  of the hemostasis valve holder  125  is set to be shorter than that of the small diameter part  1151  of the hemostasis valve holder  115 , and the length in the axis direction of a large diameter part  1252  of the hemostasis valve holder  125  is set to be longer than that of the large diameter part  1152  of the hemostasis valve holder  115 . 
     Suppose that a gap is generated between the step part  62  and the first end surface  61  of the hemostasis valve  26 , and the opening  404  and the step part  406  of the outer needle hub  34 , and also between the cylindrical part  260  of the hemostasis valve  26  and the inner peripheral surface of the hollow portion  3405  of the outer needle hub  34  due to backlash or displacement of the components, deformation of the hemostasis valve  26 , or the like when the length from the end point  61   a  of the first end surface  61  to an end surface  265  on the rear end side in the cylindrical part  260  is short, for example, less than 1 mm as in the hemostasis valve  26  of the reference example. In this case, there is a possibility that the fluid flowing through the hollow portion  400  and the hollow portion  410  leaks out to the proximal end side beyond the second cylindrical part  2602  of the hemostasis valve  26 . 
     The hemostasis valve  16  and the hemostasis valve holder  115  of the third embodiment solve the problem of the hemostasis valve  26  of the reference example by setting the length of the second cylindrical part  1602  extending from the end point  61   a  of the first end surface  61  to the proximal end side to 1 mm or more, preferably 2 mm or more. 
     Tenth Modification 
     In the third embodiment, the central proximal end surface  166  is formed in the direction perpendicular to the axis L 1  direction as the hemostasis valve  16 . However, the third embodiment can also be applied to a case where the central proximal end surface  66  is inclined with respect to the axis L 1  direction and formed in parallel with the first end surface  61  and the second end surface  63  as in the hemostasis valve  6  of the first and second embodiments and the modifications thereof. In the hemostasis valve  6 , the entire portion on the inner diameter side of the cylindrical part  60  extending from the solid part  631  to the proximal end side in the axis L 1  direction is hollow. In the cylindrical part  60 , a part on the distal end side from the end point  61   a  of the first end surface  61  is referred to as a first cylindrical part, and a part extending from the end point  61   a  to the proximal end side is referred to as a second cylindrical part. The length of the second cylindrical part of the hemostasis valve  6  defined as described above is set to 1 mm or more, preferably 2 mm or more, and a thick part is provided in the second cylindrical part. In this case, the length in the axis L 1  direction of the small diameter part  51  of each of the hemostasis valve holders  5 ,  15 ,  25 ,  35 ,  75 ,  85 , and  105  is also set to correspond to the length in the axis L 1  direction of the second cylindrical part. As a result, even if a gap is generated between the step part  62  and the first end surface  61  of the hemostasis valve  6 , and the opening  404  and the step part  406  of the outer needle hub  34 , and also between the cylindrical part  60  of the hemostasis valve  6  and the inner peripheral surface of the hollow portion  3405  of the outer needle hub  34  due to backlash or displacement of the components, deformation of the hemostasis valve  6 , or the like, it is possible to suppress leakage of the fluid flowing through the hollow portion  400  and the hollow portion  410 , to the proximal end side beyond the thick part  1602   a  of the hemostasis valve  6 . Here, the second cylindrical part defined as described above corresponds to the cylindrical part of the present invention. 
     The embodiments and modifications disclosed above can be combined with each other. 
     REFERENCE SIGNS LIST 
     
         
         
           
               1  indwelling needle 
               2  inner needle 
               3  outer needle 
               4 ,  34 ,  74 ,  84  outer needle hub 
               5 ,  15 ,  25 ,  35 ,  75 ,  85  hemostasis valve holder 
               6  hemostasis valve 
               40  main body 
               41  branch part 
               42   a ,  42   b ,  342   a ,  342   b  opening 
               43  slit 
               44  indication 
               51  small diameter part 
               55   a ,  55   b  protrusion 
               56  rib 
               57  indication 
               60   a ,  60   b ,  60   c  rib 
               60   d ,  60   e ,  60   f  groove 
               344   a ,  344   b . claw 
               344  protrusion 
               405   a ,  405   b ,  405   c  groove 
               405   d ,  405   e ,  405   f  rib