Patent Publication Number: US-2019175878-A1

Title: Catheter assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a bypass continuation of PCT Application No. PCT/JP2017/029719, filed on Aug. 21, 2017, which claims priority to Japanese Application No. 2016-164497, filed on Aug. 25, 2016. The contents of these applications are hereby incorporated by reference in their entireties. 
    
    
     BACKGROUND 
     The present disclosure relates to a catheter assembly that punctures and is indwelled in a blood vessel, for example, when transfusion or the like is performed on a patient. 
     It is known to use a catheter assembly in construction of an introducing part of an infusion line in the patient at infusion. For example, a catheter assembly disclosed in WO 2011/118643 includes a first assembly including a catheter and a catheter hub for holding a catheter, and a second assembly including an inner needle inserted in the catheter and a needle hub for holding the inner needle. Furthermore, the catheter assembly is provided with a catheter operating member for performing advancement and retraction of the first assembly. 
     A user, such as a doctor or a nurse, punctures a patient with a double-layered needle having the inner needle inserted in the catheter at the time of use. Then, the catheter operating member relatively advances the first assembly with respect to the second assembly to insert the catheter in the body. Also, the second assembly is retracted relative to the first assembly and separated therefrom. After separation, the first assembly and the catheter operating member are further separated to indwell the first assembly in the patient. 
     SUMMARY 
     The catheter assembly firmly connects the first assembly to the catheter operating member in order to stably transmit operating force of the catheter operating member to the first assembly. If the first assembly and the catheter operating member are softly connected, there is a possibility that the first assembly is removed from the catheter operating member during operation. 
     However, when the first assembly and the catheter operating member are firmly connected to each other, large force is required for separating the first assembly from the catheter operating member when the first assembly is indwelled. For example, at the time of indwelling, while the catheter hub is grasped with one hand, the catheter operating member is grasped with the other hand, and they are separated with force to separate from each other. If such large force is applied, there is a possibility that a position of the catheter is displaced or that the catheter hub is contaminated because of bacteria attached when the user grasps the vicinity of an opening of the catheter hub. 
     The present invention is achieved in view of the above-described circumstances, and an object thereof is to provide a catheter assembly capable of excellently performing an advancement/retraction operation and indwelling the catheter by easily switching between restriction and allowance of separation of the catheter hub and the catheter operating member. 
     According to one embodiment, a catheter assembly includes a first assembly including a catheter and a catheter hub that fixes and holds the catheter, a second assembly including an inner needle removably inserted in the catheter and the catheter hub and a needle hub that fixes and holds the inner needle, and a catheter operating member that operates relative movement of the first assembly with respect to the second assembly. And the catheter assembly including a separation restricting mechanism provided separately from the needle hub, in which the separation restricting mechanism restricts separation of the first assembly and the catheter operating member in an inserted state in which the inner needle is inserted in the catheter and allows the separation of the first assembly and the catheter operating member in a non-inserted state in which the inner needle is separate from the catheter. 
     According to the description above, because the separation restricting mechanism of the catheter assembly is provided separately from the needle hub, the separation of the first assembly and the catheter operating member may be restricted if it is in the inserted state even when the first assembly is separated from the needle hub. Therefore, even when the first assembly is exposed from the needle hub, the connection between the first assembly and the catheter operating member continues, and the operating force of the catheter operating member is surely transmitted to the first assembly. On the other hand, the separation restricting mechanism is easily switched to a state that allows separation of the first assembly and the catheter operating member in the non-inserted state that the inner needle is separated from the catheter. As a result, the catheter operating member and the first assembly may be smoothly separated from each other without the need of large force, and the first assembly may be remained on a patient side. 
     In this case, the separation restricting mechanism may further allow the separation of the first assembly and the catheter operating member on the basis of a fact that separation of the second assembly and the catheter operating member is restricted in the inserted state and the separation of the second assembly and the catheter operating member is allowed in the non-inserted state. 
     The catheter assembly may restrict the separation of the first assembly, the second assembly, and the catheter operating member from each other by restricting the separation of the second assembly from and catheter operating member in the inserted state. Also, it is possible to easily separate the first assembly, the second assembly, and the catheter operating member from each other by allowing the separation of the second assembly and the catheter operating member in the non-inserted state. 
     In addition, the catheter operating member preferably include a connecting unit forming a part of the separation restricting mechanism and directly connecting to the second assembly, and relative movement of the connecting unit in a direction other than an axial direction of the inner needle may be restricted until the inserted state transitions to the non-inserted state. 
     The relative movement of the catheter assembly in the direction other than the axial direction of the inner needle is restricted by the connecting unit, so that it is possible to easily relatively move the first assembly along an axial center of the inner needle while inhibiting separation of the catheter operating member until the inserted state transitions to the non-inserted state. 
     Furthermore, the second assembly preferably include an auxiliary member arranged on a side closer to a proximal end than the first assembly and forms another part of the separation restricting mechanism, and the auxiliary member in which the inner needle is inserted so as to be relatively movable may be connected to the connecting unit in the inserted state. 
     The catheter assembly is provided with the auxiliary member on the side closer to the proximal end than the first assembly and the auxiliary member is connected to the connecting unit, so that the catheter operating member and the auxiliary member (second assembly) may be continuously connected in a satisfactory condition at a position where the auxiliary member is away from the needle hub. 
     In addition to the above-described configuration, the catheter operating member preferably includes a projection arranged between the first assembly and the auxiliary member. 
     In the catheter assembly, because the catheter operating member includes the projection, in an advancement operation of the catheter operating member, the projection is pressed against the first assembly and operating force may be surely transmitted to the first assembly. In contrast, in a retraction operation of the catheter operating member, the projection is pressed against the auxiliary member, and the operating force may be surely transmitted to the auxiliary member. 
     Also, the auxiliary member may include a movable member engaged with the connecting unit in the inserted state and disengaged from the connecting unit by relatively displacing with respect to the auxiliary member in the non-inserted state. 
     In this manner, because the auxiliary member includes the movable member, this may firmly connect the catheter operating member in the inserted state, and this may be easily separated from the catheter operating member by the displacement of the movable member in the non-inserted state. 
     Alternatively, the connecting member may include a movable member engaged with the auxiliary member in the inserted state and disengaged from the auxiliary member by relatively displacing with respect to the auxiliary member in the non-inserted state. 
     With a fact that the connecting unit includes the movable member also, the catheter assembly may easily switch between separation restriction of the catheter operating member and the auxiliary member and separation allowance of the catheter operating member and the auxiliary member. 
     Furthermore, the connecting unit may be directly connected to the first assembly in the inserted state. 
     As a result, the catheter assembly may connect the second assembly and the catheter operating member and connect the first assembly, and may easily switch between the separation restriction and the separation allowance of the catheter hub and catheter operating member. 
     Herein, the separation restricting mechanism preferably allows the separation of the first assembly and the catheter operating member at a stage that a needle tip of the inner needle retracts to a position in which re-exposure is inhibited in the needle hub or in the auxiliary member. 
     As a result, the catheter assembly may allow the separation of the first assembly and the catheter operating member at a stage of the exposure of the needle tip of the inner needle is inhibited, so that safety at the time of user handling is improved. 
     In addition, the connecting unit is preferably directly connected to the inner needle so as to be slidable in the catheter hub. 
     The catheter assembly may easily switch between the separation restriction and the separation allowance of the catheter hub and the catheter operating member even if the connecting unit is directly connected to the inner needle so as to be slidable in the catheter hub. 
     Alternatively, the connecting unit may also be directly connected to the inner needle so as to be slidable on a side closer to a proximal end than the catheter hub. 
     The catheter assembly may restrict the separation of the catheter hub and the catheter operating member until the inner needle exits the connecting unit and may easily allow the separation when the inner needle exits the connecting unit even if the connecting unit is directly connected to the inner needle so as to be slidable on the side closer to the proximal end than the catheter hub. 
     Furthermore, the connecting unit may include an accommodating unit covering an upper portion and a side portion of the catheter hub to accommodate the catheter hub, and a wall portion that is directly connected to the inner needle and comes into contact with the catheter hub at the time of relative movement of the catheter operating member. 
     In this manner, because the connecting unit covers an upper portion and a side portion of the catheter hub, it is possible to inhibit the needle hub and the catheter hub from coming into contact with each other when the catheter operating member moves, thereby suppressing the catheter hub from shaking, so that the first assembly may advance in a more satisfactory condition. 
     Furthermore, an inner peripheral surface forming the accommodating unit of the connecting unit is preferably separated from an outer peripheral surface of the catheter hub in a radial direction. 
     In the catheter assembly, because the inner peripheral surface of the connecting unit is separated from the outer peripheral surface of the catheter hub, when the inner needle is separated, the catheter hub may be separated from the catheter operating member without force. 
     According to the present invention, the catheter assembly is such that the catheter may be advanced/retracted and indwelled in a satisfactory condition by easily switching between restriction and allowance of the separation of the catheter hub and the catheter operating member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating a catheter assembly according to a first embodiment of the present invention. 
         FIG. 2  is an exploded perspective view of the catheter assembly in  FIG. 1 . 
         FIG. 3  is a side sectional view illustrating a separation restricting mechanism in an inserted state of the catheter assembly in  FIG. 1 . 
         FIG. 4  is a side sectional view illustrating the separation restricting mechanism in a non-inserted state of the catheter assembly in  FIG. 1 . 
         FIG. 5  is a perspective view illustrating a distal end side of a grip in  FIG. 1 . 
         FIG. 6A  is a plan sectional view illustrating the separation restricting mechanism in  FIG. 3 , and  FIG. 6B  is a plan sectional view illustrating the separation restricting mechanism in  FIG. 4 . 
         FIG. 7  is an enlarged perspective view of a safety mechanism of the catheter assembly in  FIG. 1 . 
         FIG. 8A  is a perspective view of a catheter operating member in  FIG. 1  as seen from below, and  FIG. 8B  is a perspective view of the catheter operating member as seen from a proximal end side. 
         FIG. 9A  is a first illustrative view schematically illustrating operation of the catheter assembly in  FIG. 1 ,  FIG. 9B  is a second illustrative view of operation at the time of an advancement operation of the catheter assembly in  FIG. 1 , and  FIG. 9C  is a third illustrative view of operation at the time of a retraction operation of the catheter assembly in  FIG. 1 . 
         FIG. 10A  is a fourth illustrative view of operation following  FIG. 9B ,  FIG. 10B  is a fifth illustrative view of operation following  FIG. 10A , and  FIG. 10C  is a sixth illustrative view of operation following  FIG. 10B . 
         FIG. 11  is a side sectional view partially illustrating a catheter assembly according to a first variation. 
         FIG. 12A  is a first illustrative view schematically illustrating operation of the catheter assembly in  FIG. 11 ,  FIG. 12B  is a second illustrative view of operation following  FIG. 12A ,  FIG. 12C  is a third illustrative view of operation following  FIG. 12B , and  FIG. 12D  is a fourth illustrative view of operation following  FIG. 12C . 
         FIG. 13  is a perspective view illustrating a catheter assembly according to a second embodiment of the present invention. 
         FIG. 14  is a side sectional view illustrating a separation restricting mechanism in an inserted state of the catheter assembly in  FIG. 13 . 
         FIG. 15  is a side sectional view illustrating the separation restricting mechanism in a non-inserted state of the catheter assembly in  FIG. 13 . 
         FIG. 16A  is a perspective view illustrating a movable member of a safety mechanism in  FIG. 13 , and  FIG. 16B  is a perspective view illustrating an accommodating main body of the safety mechanism in  FIG. 13 . 
         FIG. 17A  is a first illustrative view schematically illustrating operation of the catheter assembly in  FIG. 13 ,  FIG. 17B  is a second illustrative view of operation at the time of an advancement operation of the catheter assembly in  FIG. 13 , and  FIG. 17C  is a third illustrative view of operation at the time of a retraction operation of the catheter assembly in  FIG. 13 . 
         FIG. 18A  is a fourth illustrative view of operation following  FIG. 17B ,  FIG. 18B  is a fifth illustrative view of operation following  FIG. 18A , and  FIG. 18C  is a sixth illustrative view of operation following  FIG. 18B . 
         FIG. 19A  is a first side sectional view schematically illustrating a catheter assembly according to a second variation,  FIG. 19B  is a second side sectional view of operation following  FIG. 19A , and  FIG. 19C  is a third side sectional view of operation following  FIG. 19B . 
         FIG. 20A  is a perspective view illustrating a proximal end of a catheter operating member of a catheter assembly according to a third embodiment of the present invention, and  FIG. 20B  is a side sectional view schematically illustrating the catheter assembly in  FIG. 20A . 
         FIG. 21A  is a first illustrative view illustrating operation of the catheter assembly in  FIG. 20B ,  FIG. 21B  is a second illustrative view of operation following  FIG. 21A , and  FIG. 21C  is a third illustrative view of operation following  FIG. 21B . 
         FIG. 22A  is a first side sectional view schematically illustrating a catheter assembly according to a third variation,  FIG. 22B  is a second side sectional view of operation following  FIG. 22A , and  FIG. 22C  is a third side sectional view of operation following  FIG. 22B . 
         FIG. 23A  is a perspective view illustrating a proximal end of a catheter operating member of a catheter assembly according to a fourth embodiment of the present invention, and  FIG. 23B  is a side sectional view schematically illustrating the catheter assembly in  FIG. 23A . 
         FIG. 24A  is a first illustrative view illustrating operation of the catheter assembly in  FIG. 23B ,  FIG. 24B  is a second illustrative view of operation following  FIG. 24A , and  FIG. 24C  is a third illustrative view of operation following  FIG. 24B . 
         FIG. 25A  is a first side sectional view schematically illustrating a catheter assembly according to a fourth variation,  FIG. 25B  is a second side sectional view of operation following  FIG. 25A , and  FIG. 25C  is a third side sectional view of operation following  FIG. 25B . 
         FIG. 26  is a perspective view illustrating an entire configuration of a catheter assembly according to a fifth embodiment. 
         FIG. 27  is a perspective view illustrating a state in which a catheter hub is accommodated in a catheter operating member in  FIG. 26 . 
         FIG. 28A  is a first side sectional view illustrating a substantial part of the catheter operating member and the catheter hub in  FIG. 27 ,  FIG. 28B  is a second side sectional view of operation following  FIG. 28A , and  FIG. 28C  is a third side sectional view of operation following  FIG. 28B . 
         FIG. 29A  is a perspective view illustrating a catheter operating member of a catheter assembly according to a fifth variation, and  FIG. 29B  is a side sectional view schematically illustrating the catheter assembly in  FIG. 29A . 
         FIG. 30A  is a first side sectional view schematically illustrating a catheter assembly according to a sixth variation,  FIG. 30B  is a second side sectional view of operation following  FIG. 30A , and  FIG. 30C  is a third side sectional view of operation following  FIG. 30B . 
     
    
    
     DETAILED DESCRIPTION 
     Preferred embodiments of a catheter assembly according to the present invention are hereinafter described in detail with reference to the accompanying drawings. 
     The catheter assembly according to the present invention is used, for example, to form an introducing unit of an infusion agent or a blood product when performing infusion, transfusion or the like on a patient (living body). The catheter assembly may be configured as a catheter longer in length than a peripheral venous catheter (for example, central venous catheter, PICC, midline catheter and the like). Note that the catheter assembly may also be configured as the peripheral venous catheter. The catheter assembly is not limited to a venous catheter and may be configured as an arterial catheter such as a peripheral arterial catheter. 
     First Embodiment 
     As illustrated in  FIGS. 1 and 2 , a catheter assembly  10  according to a first embodiment is provided with a catheter  12 , an inner needle  14 , a catheter hub  20 , and a housing  30  (needle hub). The catheter  12  and the catheter hub  20  are connected and fixed to each other to form a first assembly  16 . The inner needle  14  and the housing  30  are connected and fixed to each other to form a second assembly  18 . The first assembly  16  also includes a valve mechanism  50  that blocks a proximal end of the catheter hub  20 . The second assembly  18  includes a safety mechanism  60  (auxiliary member) that accommodates a needle tip  15  of the inner needle  14  so as not to be exposed after use. Furthermore, the catheter assembly  10  is provided with a catheter operating member  80  that operates relative movement of the first assembly  16  with respect to the second assembly  18 . 
     The first assembly  16  is an instrument separated from the second assembly  18  and indwelled in a patient when the catheter assembly  10  is used. For example, in a state in which the catheter  12  is inserted in a blood vessel of the patient, the first assembly  16  is such that a proximal end portion of the catheter  12  and the catheter hub  20  are exposed on the skin of the patient and the exposed portion is adhered with tape or the like. Thereafter, the user removes the valve mechanism  50  from the catheter hub  20 , and connects an infusion tube not illustrated to the proximal end of the catheter hub  20 . As a result, a infusion agent or the like is supplied from the infusion tube to the patient via the first assembly  16 . 
     The catheter  12  has moderate flexibility and is provided with a lumen  12   a  formed along an axial center thereof so as to penetrate the same. The lumen  12   a  is formed to have such a diameter that the inner needle  14  may be accommodated therein and the infusion agent or the like may flow therethrough. The proximal end of the catheter  12  is fixed to a distal end in the catheter hub  20  by an appropriate fixing method such as fusion, adhesion, or caulking. A length of the catheter  12  may be designed according to a purpose and various conditions; for example, this is set to approximately 14 to 500 mm, or approximately 30 to 400 mm, or approximately 76 to 200 mm. 
     As components of the catheter  12 , soft resin materials are preferably used, and examples thereof include, for example, fluorine resins such as polytetrafluoroethylene (PTFE), an ethylene tetrafluoroethylene copolymer (ETFE), and a perfluoroalkoxy fluorine resin (PFA), olefin resins such as polyethylene and polypropylene or a mixture thereof, polyurethane, polyester, polyamide, a polyether nylon resin, a mixture of an olefin resin and an ethylene/vinyl acetate copolymer and the like. 
     The catheter hub  20  is harder than the catheter  12  and is formed into a cylindrical shape elongated in an axial direction. In detail, a large-diameter portion  21  on a proximal end side, a transition portion  22  connected to the large-diameter portion  21  and tapered in a distal end direction, and a small-diameter portion  23  connected to the transition portion  22  and extending in the distal end direction are included. A flange  24  projecting radially outward and circumferentially circling is formed on a proximal end side outer peripheral surface of the large-diameter portion  21 . 
     As illustrated in  FIG. 3 , the catheter hub  20  has a hollow portion  25  communicated with the lumen  12   a  of the catheter  12 . The hollow portion  25  has a tapered shape corresponding to outer shapes of the large-diameter portion  21 , the transition portion  22 , and the small-diameter portion  23 . The catheter  12  is inserted and fixed to the hollow portion  25  of the small-diameter portion  23 . In the hollow portion  25  of the large-diameter portion  21 , the valve mechanism  50  is inserted in an initial state. Note that, although not illustrated, the hollow portion  25  may accommodate a hemostasis valve that inhibits backflow of blood at the time of puncture with the inner needle  14 , a plug that penetrates the hemostatic valve in accordance with insertion of a connector of the infusion tube to enable infusion and the like. 
     Components of the catheter hub  20  are not especially limited; for example, thermoplastic resins such as polypropylene, polycarbonate, polyamide, polysulfone, polyallylate, and a methacrylate-butylene-styrene copolymer may be used. 
     As illustrated in  FIGS. 2 and 3 , the valve mechanism  50  has a function of blocking the proximal end of the catheter hub  20 , thereby improving a sealing performance and a sanitary property of the first assembly  16  in the initial state, and inhibiting leakage of the blood flowing into the hollow portion  25  from the lumen  12   a  of the catheter  12 . The valve mechanism  50  includes a valve main body  51  mainly made of an elastic material and a connector  55  connected and fixed to a proximal end side of the valve main body  51  made of a resin material harder than that of the valve main body  51 . 
     The valve main body  51  includes an inserted portion  52  inserted in the hollow portion  25  of the catheter hub  20 , a disk-shaped base portion  53  connected to a proximal end of the inserted portion  52 , and a coupling projection  54  projecting from a central portion of the base portion  53  in a proximal end direction. Also, the valve main body  51  has a hole  51   a  inside the inserted portion  52 , and has a valve hole  51   b  communicated with the hole  51   a  and penetrating in an axial direction inside the base portion  53  and the coupling projection  54 . The inner needle  14  is arranged in the hole  51   a  and the valve hole  51   b  in the initial state. The valve hole  51   b  self-closes as the inner needle  14  is removed. 
     The inserted portion  52  is elastically deformed in a state of being inserted in the hollow portion  25  and is brought into close contact with an inner surface of the large-diameter portion  21  with appropriate sealing force. The base portion  53  projects radially outward of the inserted portion  52  to close the proximal end of the catheter hub  20 . The coupling projection  54  is a portion for coupling the valve main body  51  to the connector  55  and is provided with an annular concave portion  54   a  on an outer peripheral surface near the base portion  53 . 
     The connector  55  is provided with a distal end tubular portion  56  having a distal end accommodating unit  56   a  in which the base portion  53  is accommodated and a proximal end tubular portion  57  having a proximal end accommodating unit  57   a  in which the coupling projection  54  is accommodated. An outer annular convex portion  58  projecting radially outward is provided on a distal end side outer peripheral surface of the distal end tubular portion  56 . In the initial state, the outer annular convex portion  58  is arranged in the vicinity of the proximal end of the catheter hub  20  (flange  24 ) and serves as a position for receiving operating force when the catheter operating member  80  advances. 
     An inner annular convex portion  57   b  projecting radially inward is provided on a distal end side inner peripheral surface of the proximal end tubular portion  57  forming the proximal end accommodating unit  57   a . The inner annular convex portion  57   b  is engaged with an annular concave portion  54   a  of the coupling projection  54  inserted in the proximal end accommodating unit  57   a  to firmly couple the valve main body  51  and the connector  55 . Furthermore, on an outer peripheral surface of the proximal end tubular portion  57 , a constricted portion  59  that is tapered radially inward from front and rear outer peripheral surfaces is provided. In the initial state, an arm  63  of the safety mechanism  60  to be described later is caught by the constricted portion  59  and the arm  63  is detached during use, so that the valve mechanism  50  and the safety mechanism  60  may be separated (refer also to  FIG. 4 ). 
     With reference to  FIG. 1  again, the second assembly  18  is an instrument that forms a wound and insertion guide the catheter  12  while the catheter assembly  10  is used and is separated from the first assembly  16  to be discarded when the first assembly  16  is indwelled. 
     The inner needle  14  of the second assembly  18  is formed into a hollow tube having rigidity capable of puncturing the skin of a living body. The inner needle  14  is formed to be longer than an entire length of the catheter  12 , and is provided with a sharp needle tip  15  at a distal end thereof and a needle hole  14   a  inside thereof in an axial direction. In the initial state illustrated in  FIG. 1 , the inner needle  14  penetrates through the lumen  12   a  of the catheter  12  and the hollow portion  25  of the catheter hub  20  to form a multi-layered needle and exposes the needle tip  15  from the distal end of the catheter  12 . Note that it is possible to cut out a part of an outer peripheral surface of the inner needle  14  in the axial direction to form a groove, or a lateral hole communicated with the needle hole  14   a  may be provided. The inner needle  14  may also be a solid needle. 
     The inner needle  14  may be formed of, for example, a metal material such as stainless steel, aluminum or an aluminum alloy, and titanium or a titanium alloy, a hard resin, ceramics and the like. The inner needle  14  is firmly fixed to a needle holding member  40  of the housing  30  by an appropriate fixing method (fusion, adhesion, insert molding and the like). 
     In the initial state, the housing  30  has an elongated bowl shape for accommodating the first assembly  16 , the inner needle  14 , the safety mechanism  60 , and the catheter operating member  80 , and forms a grip used when the user pierces with the multi-layered needle. In detail, as illustrated in  FIG. 2 , a lower wall  31  having a guide groove  31   a  in a central portion in a width direction (lateral direction) and a pair of side walls  32  projecting upward from both sides of the lower wall  31  are provided (refer also to  FIG. 5 ), and an accommodating space  30   a  is formed between the lower wall  31  and the pair of side walls  32 . In addition, the housing  30  is provided with the needle holding member  40  for holding the inner needle  14  on a proximal end side, and a supporting member  45  for supporting the multi-layered needle from below on a distal end side. 
     The guide groove  31   a  of the lower wall  31  is concave downward in an arc shape, and the safety mechanism  60  is slidably arranged therein. In addition, in the guide groove  31   a  on the proximal end side, a mounting hole not illustrated on which the needle holding member  40  is mounted is provided. Note that the needle holding member  40  may also be formed integrally with the housing  30 . 
     The pair of side walls  32  extends in parallel in a longitudinal direction together with the lower wall  31  with a proximal end side and an intermediate side formed to have a certain height and a distal end side formed higher than the intermediate side. A groove-shaped rail portion  33  is provided on an inner surface in an upper part on the distal end side of each side wall  32 . Each of the pair of rail portions  33  is connected to an open guiding unit  33   a  in the upper part on the distal end side of each side wall  32  and linearly extends in each side wall  32  in the proximal end direction, and is connected to an upper surface on the intermediate side of each side wall  32 . The pair of rail portions  33  accommodates a side edge  81   a  of the catheter operating member  80  and guides advancement and retraction of the catheter operating member  80 . In addition, the open guiding unit  33   a  is cut out on the upper side of the housing  30 , thereby allowing the catheter operating member  80  to bend. 
     Furthermore, as illustrated in  FIGS. 2 and 5 , one side wall  32  of the pair of side walls  32  has a bulging portion  34  bulging outward in the width direction. Between the lower wall  31  of the bulging portion  34  and the rail portion  33 , an arranging concave portion  35  is cut out from the distal end of the side wall  32  in the proximal end direction. In addition, an upper and lower pair of bearing holes  36  for rotatably attaching the supporting member  45  is provided on the lower wall  31  and the side wall  32  at a position where the arranging concave portion  35  is formed. 
     The supporting member  45  includes an axial rod  46  rotatably attached to the pair of bearing holes  36 , a supporting main body  47  projecting from an axial center of the axial rod  46  in a direction orthogonal to this, and an upper projection  48  provided at an upper end of the axial rod  46 . The supporting main body  47  is formed into a crank shape as seen from the front and elastically supports the catheter  12 . The upper projection  48  has a guide concave portion  48   a  connected to the rail portion  33  on an inner side in a width direction and the side edge  81   a  of the catheter operating member  80  is arranged in the guide concave portion  48   a  in the initial state. 
     As illustrated in  FIGS. 1 and 5 , in the initial state, the supporting member  45  is such that the supporting main body  47  is arranged on an inner side of the side walls  32  (under the catheter  12 ) by the axial rod  46  to stand by so as to be able to support the catheter  12 . At that time, the side edge  81   a  (refer to  FIG. 2 ) of the catheter operating member  80  is located in the guide concave portion  48   a  of the upper projection  48  to restrict the rotation of the axial rod  46 . In use, when downward pressing force is applied from the user to the catheter operating member  80 , the supporting main body  47  supports the catheter  12  from below and suppresses bending of the catheter  12 . 
     As the catheter operating member  80  advances, the side edge  81   a  of the catheter operating member  80  exits the guide concave portion  48   a , and a side plate  92  of the catheter operating member  80  comes into contact with the supporting main body  47  and rotate the supporting main body  47  toward the outside of the side wall  32 . As a result, the supporting member  45  smoothly delivers the first assembly  16 , the safety mechanism  60 , and the catheter operating member  80  from the housing  30 . 
     The resin material forming the housing  30  (including the needle holding member  40  and the supporting member  45 ) is not especially limited, and the materials cited with the catheter hub  20  may be appropriately selected, for example. No that, in the catheter assembly  10  according to this embodiment, the safety mechanism  60  and the catheter operating member  80  are exposed on an upper side. Alternatively, the catheter assembly  10  may be configured to cover the catheter operating member  80 , the safety mechanism  60  and the like by forming an upper wall on or attaching a lid to the housing  30 . 
     On the other hand, the safety mechanism  60  in which the inner needle  14  is arranged so as to penetrate the same in the initial state accommodates the needle tip  15  moving as the inner needle  14  is withdrawn from the first assembly  16  and inhibits re-exposure of the needle tip  15 . As illustrated in  FIGS. 2 to 4, 6A, and 6B , the safety mechanism  60  is formed into a telescope shape provided with an inner tube  61  and an outer tube  71  that accommodates the inner tube  61  so as to be relatively movable. 
     The inner tube  61  having a distal end located on a side closer to the proximal end than a distal end of the outer tube  71  in the initial state connects to hold the valve mechanism  50 . The inner tube  61  is provided with a box body  62 , a pair of arms  63  integrally formed on side surfaces of the box body  62 , and an inner tubular portion  64  extending from the box body  62  in the proximal end direction. An insertion hole  61   a  through which the inner needle  14  passes is formed to penetrate inside the box body  62  and the inner tubular portion  64 . 
     The box body  62  is formed into a rectangular parallelepiped shape having rounded corners in four directions, and a cavity  62   a  communicated with the insertion hole  61   a  is provided therein. In the cavity  62   a , a shutter  65  for inhibiting the re-exposure of the needle tip  15  is arranged. The shutter  65  is formed into a U-shaped flat spring in a side sectional view. In a state in which the inner needle  14  is arranged in the cavity  62   a , the shutter  65  is accommodated in an elastically deformed state in a space above the inner needle  14 , and ends on a side opposite to a U-shaped curved portion are brought closer to each other. When the needle tip  15  of the inner needle  14  retracts toward the proximal end than the shutter  65 , the shutter  65  resiliently restores and opens in the cavity  62   a , so that this faces the needle tip  15  of the inner needle  14  in a planar manner. 
     The pair of arms  63  is coupled to the side surfaces in vertical direction of the box body  62  and extends in the distal end direction above and below the box body  62 . Hooks  63   a  projecting inward in a width direction are provided inside distal ends of the arms  63  in an extending direction. Each arm  63  is shaped so that the hook  63   a  expands outward in the width direction in a natural state in which external force does not act. In contrast, each arm  63  is elastically pressed so that the hook  63   a  tilts inward by the outer tube  71 , and is caught by the constricted portion  59  of the valve mechanism  50  in the initial state (the state in which the inner tube  61  is accommodated in the outer tube  71 ). 
     On the other hand, the inner tubular portion  64  of the inner tube  61  is formed into a cylindrical shape that may be accommodated in an outer tubular side hollow portion  73   a  of the outer tube  71 . As illustrated in  FIGS. 6A and 6B , a stopper  66  that inhibits separation of the inner tube  61  and the outer tube  71  in the initial state and an allowance space  64   a  communicated with the insertion hole  61   a  in which the stopper  66  is arranged so as to be displaced are provided near a distal end of the inner tubular portion  64  (position in the vicinity of the box body  62 ). As illustrated in  FIG. 7 , a separation restricting convex portion  67  projecting radially outward is provided on a proximal end side outer peripheral surface of the inner tubular portion  64 . 
     Furthermore, as illustrated in  FIG. 3 , the insertion hole  61   a  of the inner tubular portion  64  is formed somewhat larger in diameter on the proximal end side, and a retaining member  68  is accommodated on the proximal end side of the insertion hole  61   a  and the outer tubular side hollow portion  73   a  of the outer tube  71 . The retaining member  68  has a convex shape having a disk-shaped collar portion  69  in a side sectional view and a projecting tube  70  projecting from the collar portion  69  in the distal end direction. In the projecting tube  70 , a hole  70   a  in which the inner needle  14  is movably arranged is provided. 
     Herein, an outer shape of the inner needle  14  is gradually made thicker (wider) from a body portion toward the needle tip  15 , and a width in the vicinity of the needle tip  15  is wider than a diameter of the hole  70   a . Therefore, when the inner needle  14  retracts relative to the retaining member  68 , the outer peripheral surface thereof in the vicinity of the needle tip  15  is caught by the projecting tube  70  of the retaining member  68  and removal from the retaining member  68  is inhibited. 
     In contrast, the outer tube  71  is provided with an accommodating body  72  and an outer tubular portion  73  extending from the accommodating body  72  in the proximal end direction. The accommodating body  72  is formed into a cylindrical shape larger than the box body  62  of the inner tube  61 . A cylindrical arranging space  72   a  in which a part of the valve mechanism  50  and the distal end side of the inner tube  61  (the box body  62 , the pair of arms  63  and the like) are arranged in the initial state is provided inside the accommodating body  72 . 
     As illustrated in  FIG. 7 , sliding grooves  74  parallelly extending in an axial direction of the accommodating body  72  in which the pair of arms  63  is slidably arranged are provided in upper and lower positions on an inner surface of the accommodating body  72  forming the arranging space  72   a . Furthermore, on an outer peripheral surface of the accommodating body  72 , a pair of projected strips  75  projecting outward in a width direction is provided. The pair of projected strips  75  is located on a side lower than an axial center of the accommodating body  72  (closer to the lower wall  31  of the housing  30 ) and projects in directions opposite to each other and linearly extends in the axial direction of the accommodating body  72 . 
     The outer tubular portion  73  is formed to be longer than the inner tubular portion  64  of the inner tube  61  and provided with the outer tubular side hollow portion  73   a  communicated with the arranging space  72   a  and extending in the axial direction. A rear wall  76  surrounding the outer tubular side hollow portion  73   a  is provided on a proximal end of the outer tubular portion  73  and a proximal end opening  76   a  in which the inner needle  14  is inserted is formed in a central portion of the rear wall  76 . The collar portion  69  of the retaining member  68  is formed to have a diameter larger than that of the insertion hole  61   a  of the inner tube  61  and the proximal end opening  76   a  of the outer tube  71  and is inhibited from dropping from the outer tube  71 . 
     As illustrated in  FIGS. 6A and 6B , an elongated hole  77  communicated with the outer tubular side hollow portion  73   a  and extending in the axial direction of the outer tubular portion  73  is formed on an outer peripheral surface on a proximal end side of the outer tubular portion  73 . The elongated hole  77  in which a separation restricting convex portion  67  of the inner tube  61  is arranged inhibits the inner tube  61  from dropping from the outer tube  71  and defines a range of relative movement of the inner tube  61  with respect to the outer tube  71 . A stopper window  78  communicated with the outer tubular side hollow portion  73   a  and facing the allowance space  64   a  of the inner tube  61  in the initial state is provided on the distal end side outer peripheral surface of the outer tubular portion  73 . 
     As illustrated in  FIG. 6A , in the initial state, the safety mechanism  60  is such that the stopper  66  is arranged in the stopper window  78  of the outer tube  71  and is inhibited from displacing inward by the inner needle  14  inserted in the allowance space  64   a  of the inner tube  61 . Therefore, the stopper  66  is caught by the outer tube  71  to restrict the relative movement of the inner tube  61  with respect to the outer tube  71 . On the other hand, as illustrated in  FIG. 6B , when the needle tip  15  of the inner needle  14  moves toward the proximal end than the stopper  66 , the stopper  66  may move in the allowance space  64   a . Therefore, the inner tube  61  becomes movable relative to the outer tube  71 , and when the inner tube  61  advances, the stopper  66  pushed by the outer tube  71  faces the insertion hole  61   a  in the allowance space  64   a.    
     With reference to  FIGS. 1 and 2  again, the catheter operating member  80  is operated by the user to relatively advance and retract the first assembly  16  with respect to the inner needle  14  and the housing  30 . Especially, the catheter operating member  80  is mounted on the safety mechanism  60  connecting the first assembly  16  and is configured to directly hold the catheter  12  in the initial state. Specifically, the catheter operating member  80  includes an operating plate  81  extending in a longitudinal direction of the housing  30 , a hub arranging unit  82  coupled to a proximal end of the operating plate  81  in which the catheter hub  20  is arranged, and a connecting unit  84  coupled to a proximal end of the hub arranging unit  82  to accommodate the safety mechanism  60 . 
     The operating plate  81  is a portion that is directly operated with a finger of the user placed thereon. A pair of side edges  81   a  projecting outward in a width direction of the operating plate  81  is arranged on the pair of rail portions  33  of the housing  30  in the initial state. Because the operating plate  81  is sufficiently thin, this has flexibility with which this may be bent in a direction orthogonal to a surface direction of the operating plate  81 , that is, in a direction away from the inner needle  14  (refer to  FIG. 9B ). A material forming the operating plate  81  (catheter operating member  80 ) is not especially limited, and for example, the material cited with the catheter hub  20  may be appropriately selected. 
     As illustrated in  FIGS. 1, 8A, and 8B , an upper rib  85  and a tab  86  are provided on an upper surface of the operating plate  81 , a distal end warped portion  87  is provided on a distal end of the operating plate  81 , and a holding unit  88  and a lower rib  89  are provided on a lower surface of the operating plate  81 . 
     One or more (three in  FIG. 8A ) holding units  88  of the catheter operating member  80  are provided in a longitudinal direction of the operating plate  81  and are brought into contact with an outer peripheral surface of the catheter  12  at each portion to hold the same. Each holding unit  88  is formed of a pair of projections  90  projecting downward from the lower surface of the operating plate  81 . The pair of projections  90  is symmetrical to each other across an intermediate portion in the width direction of the operating plate  81  and is formed into a wide rectangular shape. The catheter  12  is held by being caught by clicks  90   a  of the pair of projections  90  to be held between the pair of projections  90  at the time of assembly with the catheter operating member  80 . 
     The hub arranging unit  82  of the catheter operating member  80  is formed to be longer than the catheter hub  20  in an axial direction and accommodates the catheter hub  20  therein. The hub arranging unit  82  includes an upper plate  91  continued from the operating plate  81  at the same height and a pair of side plates  92  coupled to a lower surface of the upper plate  91  and extending in the proximal end direction. A lower side of the hub arranging unit  82  is an opening portion  93  in which a space of the hub arranging unit  82  is opened. 
     The upper plate  91  is formed to be slightly narrower than the pair of side edges  81   a  of the operating plate  81 . The upper plate  91  partially covers only a distal end side (small-diameter portion  23 ) of the catheter hub  20 , thereby forming an exposing portion  82   a  to expose a proximal end side (the transition portion  22  and the large-diameter portion  21 ) of the catheter hub  20  on a side closer to the proximal end than the upper plate  91 . A distal end side of the exposing portion  82   a  is formed into a substantially triangular shape that becomes gradually narrower toward the distal end. As a result, in the initial state, a distal end side of the small-diameter portion  23  of the catheter hub  20  and the upper plate  91  are sufficiently brought close to each other, and the catheter  12  may be held in a satisfactory condition by the operating plate  81 . 
     A pair of side plates  92  is continuous to both side edges of the upper plate  91  and extends in parallel from a boundary between the operating plate  81  and the upper plate  91  in the proximal end direction. The pair of side plates  92  is accommodated inside the pair of side walls  32  of the housing  30  and is spaced apart with a width with which this may be out of contact with the flange  24  of the catheter hub  20 . A triangular coupling block  94  having a distal end face at right angle with the upper plate  91  and a proximal end face inclined is formed on the lower surface of the upper plate  91  and inside a distal end of the pair of side plates  92 . The upper plate  91  and the pair of side plates  92  are firmly connected by the coupling block  94 . 
     The connecting unit  84  is coupled to the proximal ends of the pair of side plates  92  and covers an upper portion and both side portions of the outer tube  71  (accommodating body  72 ) of the safety mechanism  60 . In detail, this includes a pair of proximal end side plates  95  connected to the pair of side plates  92  and a proximal end semi-tubular portion  96  continuous to an upper portions of the pair of proximal end side plates  95  to bridge by forming an arc shape, and a mounting chamber  84   a  is formed therein. A proximal end of the connecting unit  84  serves as a proximal end communication opening  84   b  that opens the mounting chamber  84   a . Also, at the boundary between the hub arranging unit  82  and the connecting unit  84  (a distal end of the pair of proximal end side plates  95  and the proximal end semi-tubular portion  96 ), an operating projection  97  projecting radially inward to be able to transmit operating force to the catheter hub  20  and the safety mechanism  60  is provided. 
     An outer surface side of each proximal end side plate  95  is a flat surface along the pair of side walls  32  of the housing  30 . On the other hand, an inner surface side of each proximal end side plate  95  forming the mounting chamber  84   a  is an arc surface conforming to an outer diameter of the cylindrical accommodating body  72 . Also, on the inner surfaces of the proximal end side plates  95 , a pair of concave strips  98  extending from the operating projection  97  in the proximal end direction and communicated with the proximal end communication opening  84   b  is formed. In the initial state, the pair of concave strips  98  slidably accommodates the pair of projected strips  75  of the accommodating body  72 . 
     Holding convex portions  99  projecting inward in a width direction are provided on the proximal end side of the pair of proximal end side plates  95  on a side lower than the concave strips  98 . A pair of holding convex portions  99  inhibits the outer tube  71  from falling from the opening portion on the lower side of the connecting unit  84 . 
     The inner surface of the proximal end semi-tubular portion  96  is an arc surface smoothly continuing to the inner surface of each proximal end side plate  95  and conforming to the outer shape of the accommodating body  72 . Thus, the connecting unit  84  allows the accommodating body  72  to be separated only from the proximal end communication opening  84   b . In addition, a rectangular long window  96   a  elongated in the axial direction is provided on an upper portion of the proximal end semi-tubular portion  96 . The long window  96   a  allows expansion of the upper arm  63  when the pair of arms  63  of the inner tube  61  is exposed from the accommodating body  72 . 
     As illustrated in  FIGS. 3, 8A, and 8B , the operating projection  97  of the catheter operating member  80  extends in a circumferential direction on the inner peripheral surfaces of the pair of proximal end side plates  95  and the proximal end semi-tubular portion  96 . In the initial state, the operating projection  97  is arranged between the outer annular convex portion  58  of the valve mechanism  50  and the distal end of the outer tube  71  (accommodating body  72 ), and faces the proximal end face of the outer annular convex portion  58  and the distal end face of the outer tube  71  in a range of half circumference or more in the circumferential direction. Therefore, when the user applies advancing operating force for advancing the catheter operating member  80 , the operating projection  97  comes into contact with the outer annular convex portion  58 , and the advancing operating force is smoothly transmitted to the outer annular convex portion  58 . Conversely, when the user performs a retraction operating force to retract the catheter operating member  80 , the operating projection  97  comes into contact with the outer tube  71 , and the retracting operating force is smoothly transmitted to the outer tube  71 . 
     In the catheter assembly  10  configured as described above, the inner needle  14  fixed to the housing  30  is inserted in the catheter  12  to form a double-layered needle and the needle tip  15  projects from the distal end of the catheter  12  in the initial state (puncturable state) illustrated in  FIG. 1 . In addition, the operating plate  81  of the catheter operating member  80  holds the double-layered needle with appropriate holding force by holding the catheter  12  with the holding unit  88 . The operating plate  81  is arranged on the rail portion  33  of the housing  30 , so that linearity thereof is maintained. Furthermore, at the distal end of the housing  30 , the supporting member  45  stands by so as to be able to support a lower side of the double-layered needle. 
     As illustrated in  FIGS. 3 and 9A , the outer tube  71  of the safety mechanism  60  is accommodated in the connecting unit  84  of the catheter operating member  80 . In this accommodated state, relative movement of the connecting unit  84  in a vertical direction or a width direction with respect to the safety mechanism  60  is restricted. The inner tube  61  is accommodated in the outer tube  71  so as to freely advance and retract, and the pair of arms  63  interposes and hold the connector  55  of the valve mechanism  50 . Furthermore, the valve main body  51  of the valve mechanism  50  is inserted to be fitted in the catheter hub  20 . 
     That is, the valve mechanism  50  of the first assembly  16 , the safety mechanism  60  of the second assembly  18 , and the connecting unit  84  of the catheter operating member  80  form the separation restricting mechanism  11  to restrict the separation in an inserted state in which the inner needle  14  is inserted in the catheter  12 . By the separation restricting mechanism  11 , when the inserted state continues, even if the first assembly  16  is exposed from the housing  30 , this is continuously connected with the catheter operating member  80  with strong connecting strength, and advances and retracts together with the catheter operating member  80 . 
     Basically, the catheter assembly  10  according to the first embodiment is configured as described above, and a function effect thereof is described below. 
     When forming the introducing unit of the infusion into the patient, the user uses the catheter assembly  10  illustrated in  FIG. 9A  and grasps to operate the housing  30  to puncture the patient with the double-layered needle (puncture operation). At the time of puncture, the holding unit  88  holds the catheter  12  and the supporting member  45  supports the catheter  12  from below, so that bending of the double-layered needle is inhibited. 
     Then, in a punctured state of the double-layered needle, the user relatively advances the first assembly  16  with respect to the inner needle  14  and the housing  30 , and inserts the catheter  12  in the blood vessel (catheter advancement operation). At that time, the user puts his/her finger on the upper rib  85  or the tab  86  of the catheter operating member  80  and slides the catheter operating member  80  in the distal end direction. The operating plate  81  of the catheter operating member  80  is such that the distal end warped portion  87  comes into contact with the skin and the like of the patient to be bent away from the double-layered needle together with the advance in the distal end direction. As a result, each holding unit  88  sequentially removes the held catheter  12 . 
     The side plate  92  and the coupling block  94  of the catheter operating member  80  are brought into contact with the supporting member  45  when getting out of the housing  30 , thereby rotating the supporting member  45  to the outside of the housing  30 . As a result, the catheter operating member  80  and the safety mechanism  60  get out of the distal end of the housing  30  and are exposed to the outside. 
     As illustrated in  FIG. 9B , at the time of the catheter advancement operation, the operating projection  97  of the catheter operating member  80  is brought into contact with the outer annular convex portion  58  of the valve mechanism  50  and presses the same in the distal end direction. That is, the advancing operating force of the user is transmitted to the first assembly  16  to integrally advance the first assembly  16  and the safety mechanism  60 . On the other hand, when the user retracts the catheter operating member  80 , as illustrated in  FIG. 9C , the operating projection  97  comes into contact with the distal end face of the outer tube  71  and presses the same in the proximal end direction. By this, the retracting operating force of the user is transmitted to the safety mechanism  60  to integrally retract the first assembly  16  and the safety mechanism  60 . 
     After the catheter  12  is sufficiently advanced into the blood vessel by the catheter advancement operation, the housing  30  is withdrawn in the proximal end direction to remove the inner needle  14  from the patient while the catheter  12  is remained inserted (inner needle retraction operation). At that time, the user retracts the inner needle  14  and the housing  30  relative to the first assembly  16 , the safety mechanism  60 , and the catheter operating member  80  so as to separate them from the first assembly  16 . 
     In the safety mechanism  60 , because the inner needle  14  retracts toward the proximal end than the shutter  65  in the inner tube  61  at the time of the inner needle retraction operation, the shutter  65  pushed in by the inner needle  14  develops in front of the needle tip  15  to inhibit the re-exposure of the needle tip  15  (refer also to  FIG. 4 ). Also, as the inner needle  14  retracts toward the proximal end than the stopper  66 , the stopper  66  is put into a free state, and relative movement between the inner tube  61  and the outer tube  71  becomes possible (refer also to  FIG. 6B ). Furthermore, when the inner needle  14  retracts, the vicinity of the needle tip  15  is caught by the retaining member  68 . As a result, the needle tip  15  is accommodated in the safety mechanism  60  in an unremovable condition. 
     At the time of the inner needle retraction operation, the outer tube  71  is pulled by the inner needle  14  caught by the retaining member  68 . Therefore, as illustrated in  FIG. 10A , the outer tube  71  relatively retracts in the proximal end direction with respect to the first assembly  16  and the catheter operating member  80 . When the outer tube  71  retracts, the inner tube  61  relatively advances with respect to the outer tube  71  by the valve mechanism  50  of which movement is restricted by the catheter operating member  80 , and is delivered from the distal end of the outer tube  71 . As a result, the pair of arms  63  is opened, and the connection of the valve mechanism  50  by the pair of hooks  63   a  may be released (refer also to  FIG. 4 ). 
     Also, the catheter operating member  80  relatively advances with respect to the outer tube  71  because the operating projection  97  is interposed between the pair of arms  63  and the valve mechanism  50 . As a result, the outer tube  71  moves in the mounting chamber  84   a  of the connecting unit  84  in the proximal end direction to separate from the proximal end communication opening  84   b . At that time, the pair of concave strips  98  of the catheter operating member  80  guides the pair of projected strips  75  of the outer tube  71  to slide. 
     Herein, the first assembly  16  is not held by the catheter operating member  80 ; only the valve mechanism  50  is connected to the inner tube  61 . Therefore, as illustrated in  FIG. 10B , the first assembly  16  is also movable from the catheter operating member  80  in accordance with the disconnection of the valve mechanism  50  due to the expansion of the pair of hooks  63   a.    
     Therefore, as illustrated in  FIG. 10C , the first assembly  16  exits the opening portion  93  of the catheter operating member  80  (hub arranging unit  82 ). On the other hand, the catheter operating member  80  is also separated from the safety mechanism  60  (second assembly  18 ) that exits the connecting unit  84  together with the separation of the first assembly  16 . 
     That is, in a non-inserted state in which the inner needle  14  separates from the catheter  12  by the inner needle retraction operation, the separation restricting mechanism  11  has weak connecting strength to allow separation of the first assembly  16 , the safety mechanism  60 , and the catheter operating member  80  from one another. As a result, the first assembly  16  may be indwelled in the patient in a satisfactory condition. On the other hand, the second assembly  18  and the catheter operating member  80  separated from the first assembly  16  are easily discarded by the user. Note that, in the first embodiment, the connecting strength becomes zero in the non-inserted state, but the first assembly  16  may also be connected to the second assembly  18  and the catheter operating member  80  with connecting strength greater than zero such as frictional force. 
     As described above, the catheter assembly  10  may restrict separation of the first assembly  16  and the catheter operating member  80  in the inserted state by the separation restricting mechanism  11  provided separately from the housing  30 . Therefore, even when the first assembly  16  is exposed from the housing  30 , the connection between the first assembly  16  and the catheter operating member  80  continues, and the operating force of the catheter operating member  80  is surely transmitted to the first assembly  16 . On the other hand, the separation restricting mechanism  11  allows separation of the first assembly  16  from the catheter operating member  80  in the non-inserted state in which the inner needle  14  is separated from the catheter  12 . As a result, the catheter operating member  80  and the first assembly  16  may be smoothly separated from each other without large force, and the first assembly  16  may be indwelled on the patient side. 
     Especially, the catheter assembly  10  may restrict the separation of the first assembly  16 , the second assembly  18 , and the catheter operating member  80  from each other by restricting the separation of the second assembly  18  from the catheter operating member  80  in the inserted state. In contrast, it is possible to smoothly separate the first assembly  16 , the second assembly  18 , and the catheter operating member  80  from each other by allowing the separation of the second assembly  18  from the catheter operating member  80  in the non-inserted state. Also, the relative movement of the catheter operating member  80  in a direction other than the axial direction of the inner needle  14  is restricted by the connecting unit  84 , so that it is possible to easily relatively move the first assembly  16  along the axial center of the inner needle  14 . 
     Furthermore, the catheter assembly  10  is provided with the safety mechanism  60  on a side closer to the proximal end than the first assembly  16 , and the separation of the safety mechanism  60  from the connecting unit  84  is restricted in the inserted state. As a result, even in a position where the safety mechanism  60  is separated from the housing  30 , the connection between the catheter operating member  80  and the second assembly  18  is satisfactory continued. In addition, because the catheter operating member  80  includes the operating projection  97 , in the advancement operation of the catheter operating member  80 , the operating projection  97  is pressed against the first assembly  16  and the operating force may be surely transmitted to the first assembly  16 . In contrast, in the retraction operation of the catheter operating member  80 , the operating projection  97  is pressed against the safety mechanism  60 , and the operating force may be surely transmitted to the operating projection  97 . Furthermore, by allowing the separation of the first assembly  16  from the catheter operating member  80  at a stage when an exposure of the needle tip  15  is inhibited, safety at the time of user handling is improved. an 
     Note that the catheter assembly  10  is not limited to the above-described configuration, and various variations and applications may also be adopted. For example, it is possible to configure such that the catheter operating member  80  is not provided with the valve mechanism  50  and the pair of arms  63  of the inner tube  61  holds the catheter hub  20 . In this case, the connecting unit  84  of the catheter operating member  80  may be brought into contact with the proximal end of the catheter hub  20  to transmit the advancing operating force at the time of the advancement operation. Also, the catheter assembly  10  may be provided with a guide wire that is inserted in the inner needle  14  and may advance and retract with respect to the inner needle  14 . 
     Hereinafter, the variation of the catheter assembly  10  and other embodiments (second to fifth embodiments) are described. Note that, in the following description, the same reference numeral is assigned to the same component or a component having the same function as that of the catheter assembly  10  according to the first embodiment, and the detailed description thereof is omitted. 
     A catheter assembly  10 A according to a first variation illustrated in  FIG. 11  different from the catheter assembly  10  according to the first embodiment in that this is provided with a blood scattering prevention cover  100  as an auxiliary member for accommodating an inner needle  14  and has a structure of automatically retracting the inner needle  14 . A separation restricting mechanism  11 A is formed of a catheter hub  20 , a connecting unit  84  of a catheter operating member  80 A, and the blood scattering prevention cover  100 . 
     Although the structure of automatically retracting the inner needle  14  is not especially limited, for example, it may be configured to retract a needle holding member  40 A that holds the inner needle  14  by energization of an elastic member (coil spring  41  or the like) by a fact that the catheter hub  20  is separated from a housing  30 A at a predetermined distance as a trigger. Specifically, the housing  30 A is formed into a bottomed square tube shape with a distal end opened. In the housing  30 A, the blood scattering prevention cover  100 , a tubular needle holding member  40 A accommodated in the blood scattering prevention cover  100 , and a coil spring  41  for energizing the needle holding member  40 A in a proximal end direction are provided in an initial state. In the initial state, the needle holding member  40 A is engaged with the housing  30 A by a lock member  42 , and movement thereof in the proximal end direction is restricted. 
     The blood scattering prevention cover  100  includes a head piece  101  for removably coupling a catheter hub  20  in the catheter hub  20 , a distal end body portion  102  extending from the head piece  101  in the proximal end direction on which the catheter operating member  80 A is externally mounted, and a proximal end body portion  103  extending from the distal end body portion  102  in the proximal end direction by a predetermined length. An accommodation hole  100   a  in which the needle holding member  40 A is accommodated is provided inside the distal end body portion  102  and the proximal end body portion  103 . 
     A pair of head pieces  101  of the blood scattering prevention cover  100  is provided so as to interpose the inner needle  14 , and on an outer peripheral surface thereof, a catch portion  101   a  inserted in a coupling groove  20   a  provided on an inner surface of the catheter hub  20  is formed so as to project radially outward. In the initial state, the pair of head pieces  101  is such that the inner needle  14  is arranged between them and distal ends thereof are separated in opposite directions to engage the catch portion  101   a  with the coupling groove  20   a . On the other hand, when the inner needle  14  is no longer arranged between them, the distal ends are brought close to each other, thereby disengaging the catch portion  101   a  from the coupling groove  20   a.    
     The distal end body portion  102  is formed into a cylindrical shape and is fitted to the inner surface of the catheter hub  20  to seal a hollow portion  25 . The catheter operating member  80 A is provided with a connecting unit  84  in a C shape in a cross-sectional view orthogonal to a longitudinal direction on a proximal end thereof, and a C-shaped inner space is opened downward. The connecting unit  84  is slidably arranged outside the distal end body portion  102  of the blood scattering prevention cover  100  exposed from a proximal end of the catheter hub  20 . Also, on an outer peripheral surface of the distal end body portion  102 , a projection  104  facing a proximal end of the connecting unit  84  is projected. 
     On the other hand, the proximal end body portion  103  has a cylindrical shape than that of the distal end body portion  102  and is inserted to a side closer to the proximal end than a seat (annular projection  44 ) of a coil spring  41  in the housing  30 A in the initial state. The lock member  42  is arranged in an intermediate position of an outer peripheral surface of the proximal end body portion  103 . A guide projection  107  is provided on a proximal end side of the proximal end body portion  103  for guiding the lock member  42  and restricting the separation of the blood scattering prevention cover  100  from the housing  30 A. 
     The needle holding member  40 A includes an inner holding unit  105  inserted in the blood scattering prevention cover  100  to hold the inner needle  14  on a distal end thereof and an outer receiving tube  106  projecting radially outward from a proximal end of the inner holding unit  105  and further extending in a distal end direction out of the inner holding unit  105 . In a predetermined position of the outer receiving tube  106 , a through hole  106   a  through which the lock member  42  is arranged to penetrate is provided. A distal end face of the outer receiving tube  106  is configured as the seat that receives the coil spring  41 . 
     The lock member  42  is formed into a triangular shape in a side sectional view and penetrates the through hole  106   a  of the needle holding member  40 A in a state of being arranged on an outer peripheral surface of the blood scattering prevention cover  100 , and a part thereof is inserted in a locking hole  37  provided on an inner surface of the housing  30 A. As a result, the lock member  42  makes the blood scattering prevention cover  100  relatively slidable while restricting the movement of the needle holding member  40 A in the proximal end direction in the initial state. 
     Basically, the catheter assembly  10 A according to the first variation is configured as described above, and a function effect thereof is hereinafter described. As illustrated in  FIGS. 11 and 12A , the catheter assembly  10 A restricts separation of the catheter hub  20 , the connecting unit  84  of the catheter operating member  80 , and the blood scattering prevention cover  100  in an inserted state that the inner needle  14  is inserted in the catheter  12 . In this state, as in the first embodiment, puncture operation and catheter advancement operation are performed. 
     In the catheter advancement operation, as a user pushes out the catheter operating member  80 A, as illustrated in  FIG. 12B , the connecting unit  84  of the catheter operating member  80 A comes into contact with the proximal end of the catheter hub  20  to advance a first assembly  16 . At that time, while the blood scattering prevention cover  100  connected to the first assembly  16  advances, the needle holding member  40 A continues a state in which the movement is restricted by the lock member  42 . When the user retracts the catheter operating member  80 A, the connecting unit  84  comes into contact with a projection  104  (refer to  FIG. 11 ) of the blood scattering prevention cover  100  to retract the blood scattering prevention cover  100 . 
     When the catheter  12  is inserted in a patient by the catheter advancement operation, the user performs an inner needle retraction operation of retracting the inner needle  14  and the housing  30 A. In the inner needle retraction operation, as the housing  30 A and the needle holding member  40 A retract in the proximal end direction, the blood scattering prevention cover  100  relatively moves to the distal end side. As a result, the needle tip  15  of the inner needle  14  is accommodated in the blood scattering prevention cover  100 , and scattering of blood attached to the inner needle  14  is prevented. 
     Thereafter, as illustrated in  FIG. 12C , when the lock member  42  moves toward the proximal end than the blood scattering prevention cover  100 , the lock member  42  exits the locking hole  37  of the housing  30 A. Then, the needle holding member  40 A energized in the proximal end direction by the coil spring  41  retracts in the proximal end direction as the coil spring  41  elastically expands on the basis of unlocking of the lock member  42 . As a result, the inner needle  14  automatically retracts to be accommodated in the housing  30 A, and re-exposure of the needle tip  15  is prevented. 
     When the blood scattering prevention cover  100  advances to a certain extent from the housing  30 A, the guide projection  107  is caught by the annular projection  44  in the housing  30 A, so that the blood scattering prevention cover  100  is inhibited from dropping from the housing  30 A. At a stage at which the inner needle  14  exits the catheter hub  20  (in a non-inserted state in which the inner needle  14  is separated from the catheter  12 ), the head piece  101  of the blood scattering prevention cover  100  is bent inward and the coupling with the catheter hub  20  is released. Along with this, the catheter operating member  80 A may advance relative to the blood scattering prevention cover  100 . Therefore, as illustrated in  FIG. 12D , the first assembly  16  and the second assembly  18  (the blood scattering prevention cover  100 ) are separated by the catheter operating member  80 A pushing out the first assembly  16 , and the catheter operating member  80 A is separated from the first and second assemblies  16  and  18 . 
     As described above, the catheter assembly  10 A according to the first variation may also obtain the effect similar to that of the catheter assembly  10 . Especially, the second assembly  18  of the catheter assembly  10 A may further improve safety at the time of handling (disposal) by automatically retracting the inner needle  14  and accommodating in the housing  30 A. 
     Second Embodiment 
     As illustrated in  FIGS. 13 to 18C , a catheter assembly  110  according to a second embodiment is different from catheter assemblies  10  and  10 A in a structure of a safety mechanism  160  (auxiliary member) and a structure of a catheter operating member  180  corresponding to the same. Note that a configuration of a first assembly  116  is basically similar to that of the first embodiment, but a connector  55  of a valve mechanism  50  is not provided with an outer annular convex portion  58 . A separation restricting mechanism  111  is formed of the valve mechanism  50  of the first assembly  116 , the safety mechanism  160  of a second assembly  118 , and a connecting unit  184  of the catheter operating member  180 . 
     As illustrated in  FIGS. 14 to 16B , the safety mechanism  160  includes an accommodating main body  161  for accommodating a needle tip  15  of an inner needle  14  and a movable member  170  provided separately from the accommodating main body  161  and movable relative to the same. An insertion hole  161   a  of the inner needle  14  is provided inside the accommodating main body  161  and a member space  161   b  for accommodating and fixing a retaining member  68  of the inner needle  14  is formed on a proximal end side of the insertion hole  161   a . Note that the movable member  170  may be coupled to (integrally molded with) the accommodating main body  161  with a coupling arm or the like not illustrated. 
     The accommodating main body  161  includes a cylindrical portion  162  detachably attached to the connecting unit  184  of the catheter operating member  180  and a head portion  163  projecting from a central portion of a distal end face of the cylindrical portion  162  in a distal end direction. On an outer peripheral surface of the cylindrical portion  162 , a pair of projected strips  164  projecting in directions opposite to each other outward in a width direction and linearly extending in an axial direction of the cylindrical portion  162  is provided. A cutout space  165  reaching an axial center of the cylindrical portion  162  is formed on the outer peripheral surface on an upper side of the cylindrical portion  162  in an initial state. 
     The cutout space  165  includes a rectangular parallelepiped-shape deep space  165   a  provided in the vicinity of the axial center of the cylindrical portion  162  and a shallow space  165   b  continuous from an upper portion of the deep space  165   a  and having a shape larger in axial and width directions than that of the deep space  165   a  and is formed into a stepped space. The movable member  170  is accommodated in the cutout space  165  so as to be freely displaced. 
     The deep space  165   a  is provided so as to divide the insertion hole  161   a  extending in the axial direction near the distal end of the cylindrical portion  162 , thereby being communicated with the insertion hole  161   a  on both front and rear sides. In contrast, a plurality of locking pieces  166  is formed so as to project on an inner surface on a distal end side and an inner surface on a proximal end side of the cylindrical portion  162  forming the shallow space  165   b . Two locking pieces  166  on the inner surface on the distal end side are inclined diagonally downward in a proximal end direction and two locking pieces  166  on the inner surface on the proximal end side are inclined diagonally downward in a distal end direction. A plurality of locking pieces  166  is provided at the same horizontal height within the cylindrical portion  162 , and when the movable member  170  is displaced downward to get over each locking piece  166 , they cooperate with each other to lock the movable member  170 . 
     Also, the head portion  163  of the accommodating main body  161  is formed into a cylindrical shape so as to be able to fit to a proximal end accommodating unit  57   a  of the valve mechanism  50  (connector  55 ). In the initial state, the head portion  163  is inserted in the proximal end accommodating unit  57   a , so that the connector  55  of the valve mechanism  50  is in close contact with the distal end face of the cylindrical portion  162 . 
     In contrast, the movable member  170  is formed as a member having a cross shape as seen in a front view with plate-shaped vertical plate  171  and horizontal plate  172  intersecting at 90 degrees. The vertical plate  171  extends in a vertical direction to be arranged in the deep space  165   a  and the shallow space  165   b . A portion above a coupling site to the horizontal plate  172  of a proximal end face of the vertical plate  171  is formed to be a tapered surface  171   a . Furthermore, a needle tip accommodating hole  171   b  tapered to be closed is provided in a position below the coupling site to the horizontal plate  172  of the proximal end face of the vertical plate  171 . In contrast, the horizontal plate  172  is arranged in the shallow space  165   b  so as to extend in the width direction and the axial direction of the cylindrical portion  162 . 
     As illustrated in  FIG. 14 , the movable member  170  configured as described above is arranged on an upper side of the cutout space  165  and displacement downward is restricted because the inner needle  14  penetrates the deep space  165   a  in the initial state. Therefore, the vertical plate  171  of the movable member  170  plays a role as a lock function of locking the catheter operating member  180 . On the other hand, as illustrated in  FIG. 15 , when the inner needle  14  retracts from the deep space  165   a , the movable member  170  may be displaced to a lower side of the cutout space  165 . Then, this is displaced downward as the catheter operating member  180  advances, allows the needle tip accommodating hole  171   b  to face the insertion hole  61   a , and a plurality of locking pieces  166  of the cylindrical portion  162  and the horizontal plate  172  are locked. 
     Also, as illustrated in  FIGS. 13 to 15 , the connecting unit  184  of the catheter operating member  180  is formed to be longer in the axial direction than the connecting unit  84  of the first embodiment. An operating projection  197  having a shape similar to that of the first embodiment is provided at a distal end of the connecting unit  184  (boundary position of a hub arranging unit  82 ); in the initial state, the operating projection  197  is located on a side closer to a distal end than a flange  24  of a catheter hub  20 . 
     A rectangular insertion opening  184   a  in which the vertical plate  171  of the movable member  170  is inserted is provided on an upper portion and in a central portion in the width direction of the connecting unit  184 . The insertion opening  184   a  is formed so as to have dimensions in axial and width directions smaller than those of the horizontal plate  172  of the movable member  170 , inhibiting the movable member  170  from getting out of the insertion opening  184   a . In the initial state, the movable member  170  is located on the upper side of the cutout space  165  as described above, so that the vertical plate  171  is continuously arranged in the insertion opening  184   a . Therefore, advancing operating force of the catheter operating member  180  by a user is transmitted from an opening edge of the insertion opening  184   a  to the movable member  170  (vertical plate  171 ) to advance and retract the safety mechanism  160 . Because the safety mechanism  160  is connected to the first assembly  116 , the operating force of the catheter operating member  180  is eventually transmitted also to the first assembly  116 . 
     The catheter assembly  110  according to the second embodiment is basically configured as described above, and a function effect thereof is hereinafter described. As illustrated in  FIG. 17A , the separation restricting mechanism  111  of the catheter assembly  110  restricts separation of the valve mechanism  50 , the safety mechanism  160 , and the connecting unit  184  of the catheter operating member  180  in an inserted state in which the inner needle  14  is inserted in the catheter  12 . In this state, as in the first embodiment, a puncture operation and a catheter advancement operation are performed. 
     As illustrated in  FIG. 17B , in the catheter advancement operation, as the user pushes out the catheter operating member  180 , the opening edge of the insertion opening  184   a  is brought into contact with the movable member  170  and pushes out the safety mechanism  160 . As a result, the safety mechanism  160  advances and the first assembly  116  connected to the safety mechanism  160  also advances. Also, as illustrated in  FIG. 17C , when the user retracts the catheter operating member  180 , the opening edge of the insertion opening  184   a  pushes the movable member  170  in the proximal end direction and the operating projection  197  pushes the flange  24  of the catheter  12  in the proximal end direction, so that the first assembly  116  and the safety mechanism  160  are retracted. 
     When the catheter  12  is inserted in a patient by the catheter advancement operation, the user performs an inner needle retraction operation of retracting the inner needle  14  and a housing  30 . As illustrated in  FIG. 18A , in the inner needle retraction operation, the needle tip  15  moves toward the proximal end than the movable member  170 , so that the movable member  170  may be displaced downward. That is, the safety mechanism  160  and the catheter operating member  180  are unlocked, and as illustrated in  FIG. 18B , the catheter operating member  180  may advance relative to the safety mechanism  160 . 
     Also, the catheter hub  20  of which movement in the distal end direction is restricted by the operating projection  197  of the catheter operating member  180  may also advance relative to the safety mechanism  160 . As a result, as illustrated in  FIG. 18C , the first assembly  116  (valve mechanism  50 ), the second assembly  118  (safety mechanism  160 ), and the catheter operating member  180  are separated from one another. 
     In contrast, as the catheter operating member  180  advances, the movable member  170  is such that the tapered surface  171   a  on the proximal end side is pushed by the opening edge of the insertion opening  184   a  and is displaced downward in the cutout space  165 . Along with this displacement, the horizontal plate  172  gets over the four locking pieces  166  to be locked, and the vertical plate  171  blocks the insertion hole  161   a  of the accommodating main body  161  (refer to  FIG. 15 ). As a result, even when the inner needle  14  advances, the needle tip  15  is guided to the needle tip accommodating hole  171   b  of the movable member  170  and re-exposure of the needle tip  15  is inhibited. 
     As described above, the catheter assembly  110  according to the second embodiment may also obtain the effect similar to that of the catheter assembly  10 . Especially, the catheter assembly  110  may firmly connect the first assembly  116  to the catheter operating member  180  by the movable member  170  in the inserted state in which the inner needle  14  is inserted in the catheter  12  because the safety mechanism  160  includes the movable member  170 . On the other hand, it is possible to easily separate the first assembly  116  from the catheter operating member  180  by the displacement of the movable member  170  in a non-inserted state of the inner needle  14  in the catheter  12 . 
     A catheter assembly  110 A according to a second variation illustrated in  FIGS. 19A to 19C  has a structure of collectively performing separation restriction of a first assembly  116  and a catheter operating member  180  by a movable member  170  of a safety mechanism  160 . A separation restricting mechanism  111 A is formed of a catheter hub  120 , the safety mechanism  160 , and a connecting unit  184  of the catheter operating member  180 . 
     Therefore, the first assembly  116  is provided with an extending portion  121  extending from a proximal end of a catheter hub  120  (or a valve mechanism  50 ) in a proximal end direction. The extending portion  121  is arranged between an accommodating main body  161  and the catheter operating member  180 , and the movable member  170  is caught thereby. A locking hole  121   a  through which the movable member  170  penetrates in an initial state is provided on a proximal end side of the extending portion  121 . The locking hole  121   a  is arranged to face an insertion opening  184   a  of the catheter operating member  180  in a position overlapping with the movable member  170 . 
     The connecting unit  184  of the catheter operating member  180  is formed into a C shape in a cross-sectional view orthogonal to an axial direction, and is attached so as to enclose an outer peripheral surface of the accommodating main body  161 . As a result, the catheter operating member  180  does not move any more relative to the accommodating main body  161  in a vertical direction or a width direction. In the initial state, the connecting unit  184  is provided in a position not overlapping with the extending portion  121  of the first assembly  116 . 
     As illustrated in  FIG. 19A , the catheter assembly  110 A configured as described above is such that the movable member  170  is arranged in an upper position of a cutout space  165  because an inner needle  14  is inserted in the cutout space  165  in the initial state. Therefore, the movable member  170  is inserted in the locking hole  121   a  and the insertion opening  184   a  to restrict separation of the first assembly  116 , the safety mechanism  160 , and the catheter operating member  180 . 
     Therefore, as illustrated in  FIG. 19B , when the user performs an advancement operation of the catheter operating member  180 , advancing operating force thereof is transmitted to the first assembly  116  and the safety mechanism  160  via the movable member  170 , and they advance integrally. The first assembly  116  and the catheter operating member  180  are continuously locked by the movable member  170  until the needle tip  15  of the inner needle  14  moves in a proximal end direction than the movable member  170 . 
     When the inner needle  14  exits the catheter  12  and the needle tip  15  moves in the proximal end direction than the movable member  170 , the movable member  170  may be displaced to a lower portion of the cutout space  165 . Therefore, as illustrated in  FIG. 19C , the first assembly  116  and the catheter operating member  180  may be ejected from a distal end of the safety mechanism  160 , and along with this ejection, the first assembly  116  and the catheter operating member  180  are separated. 
     As described above, the catheter assembly  110 A according to the second variation also restricts separation of the first assembly  116 , a second assembly  118 , and the catheter operating member  180  in an inserted state in which an inner needle  14  is inserted in a catheter  12 . Therefore, the catheter operating member  180  may smoothly operate the first assembly  116 . On the other hand, when a needle tip  15  moves toward the proximal end than the movable member  170  in the non-inserted state in which the inner needle  14  exits the catheter  12 , the first assembly  116 , the second assembly  118 , and the catheter operating member  180  are allowed to be separated and connecting strength to each other becomes weak. Therefore, the first assembly  116  is indwelled on a patient side in a satisfactory condition. 
     Third Embodiment 
     As illustrated in  FIGS. 20A to 21C , a catheter assembly  210  according to a third embodiment is different from catheter assemblies  10 ,  10 A,  110 , and  110 A in a structure of a catheter operating member  280  and a structure of a safety mechanism  260  (auxiliary member) corresponding to the same. A separation restricting mechanism  211  is formed of a valve mechanism  250  of a first assembly  216 , the safety mechanism  260  of a second assembly  218 , and a cam unit  281  (connecting unit) of the catheter operating member  280 . 
     The catheter operating member  280  is formed as a plate-shaped plate body  282  elongated in an axial direction, and includes the cam unit  281  on a proximal end side of the plate body  282 . The catheter operating member  280  also includes a catch hole  283  for catching the first assembly  216  on a side closer to a distal end than the cam unit  281 . 
     The cam unit  281  includes a cam main body  284  (movable member) engaged with an inner needle  14 , a cam hole  285  through which the cam main body  284  penetrates so as to be displaceable, a coupler  286  for coupling the plate body  282  and the cam main body  284  (not illustrated in  FIGS. 20B to 21C ). The cam main body  284  is formed into a trapezoidal shape in a side sectional view, and a distal end face  284   a  thereof is inclined toward the proximal end from an upper end toward a lower end. On a lower end side of the cam main body  284 , there is provided an engagement hole  287  in which the inner needle  14  is inserted so as to penetrate from the distal end face  284   a  to a proximal end face  284   b . The cam hole  285  is formed into a rectangular shape somewhat larger than the cam main body  284  in a plan view and the cam main body  284  is arranged inside. The coupler  286  has sufficient flexibility and allows the cam main body  284  to be displaced up and down relative to the plate body  282 . 
     As is the case with the second embodiment, the safety mechanism  260  is formed to have a cylindrical accommodating main body  261  and includes a cutout space  265  cut out inward from an outer peripheral surface in which the cam main body  284  is inserted and includes a cavity  261   a  that may accommodate a shutter  65  as is the case with the first embodiment. Although not illustrated, a retaining member  68  is accommodated on a proximal end side of the cavity  261   a . The cutout space  265  is communicated with an insertion hole  61   a  of the accommodating main body  261  in which the cam main body  284  is arranged such that the engagement hole  287  of the cam main body  284  faces the insertion hole  61   a  in an initial state. 
     In contrast, an extending portion  251  of the first assembly  216  (valve mechanism  250 ) has a plate shape having a predetermined length in an axial direction, and is interposed between the safety mechanism  260  and the catheter operating member  280  in the initial state. A catch projection  252  projecting upward (side opposite to the accommodating main body  261 ) is provided on a proximal end of the extending portion  251 , and the catch projection  252  is inserted in the catch hole  283  of the catheter operating member  280 . 
     The catheter assembly  210  according to the third embodiment is basically configured as described above, and a function effect thereof is hereinafter described. The separation restricting mechanism  211  of the catheter assembly  210  restricts separation of the valve mechanism  250 , the safety mechanism  260 , and the cam unit  281  of the catheter operating member  280  in an inserted state in which the inner needle  14  is inserted in a catheter  12 . In this state, as in the first and second embodiments, a puncture operation and a catheter advancement operation are performed. 
     As illustrated in  FIG. 21A , in the catheter advancement operation, a user pushes out the catheter operating member  280  in a distal end direction relative to a housing  30 , so that the cam main body  284  transmits advancing operating force to the safety mechanism  260  to advance the safety mechanism  260 . In addition, the catheter operating member  280  pushes out the catch projection  252  inserted in the catch hole  283  to advance the first assembly  216  together with the safety mechanism  260 . 
     Next, the user performs an inner needle retraction operation to retract the housing  30 . In the inner needle retraction operation, a needle tip  15  is accommodated in the accommodating main body  261  of the safety mechanism  260  as the inner needle  14  retracts. When the needle tip  15  moves in a proximal end direction than the shutter  65 , the shutter  65  develops to face the insertion hole  61   a . This inhibits re-exposure of the inner needle  14 . 
     Furthermore, as illustrated in  FIG. 21B , when the needle tip  15  further moves toward the proximal end than the cam main body  284 , the needle tip  15  exits the engagement hole  287 , so that the cam main body  284  may be displaced up and down. Note that the inner needle  14  is inhibited from getting out in the proximal end direction by the retaining member  68  in the safety mechanism  260 . As a result, the catheter operating member  280  and the safety mechanism  260  may be separated from each other. 
     Therefore, when the user performs the advancement operation of the catheter operating member  280 , the cam main body  284  is displaced upward with the inclined distal end face  284   a  abutting a wall on a distal end side of the accommodating main body  261  (cutout space  265 ). That is, as illustrated in  FIG. 21C , the catheter operating member  280  of which separation restriction is released separates from the safety mechanism  260 . While the extending portion  251  is interposed between the safety mechanism  260  and the catheter operating member  280 , the first assembly  216  follows the operation of the catheter operating member  280 , but this is separated from both members as the catheter operating member  280  is separated from the safety mechanism  260 . 
     As described above, the catheter assembly  210  according to the third embodiment may also restrict the separation of the first assembly  216 , the second assembly  218 , and the catheter operating member  280  by the cam unit  281  in the inserted state in which the inner needle  14  is inserted in the catheter  12 . On the other hand, when the needle tip  15  moves in the proximal end direction than the cam main body  284  in a non-inserted state in which the inner needle  14  separates the catheter  12 , the first assembly  216 , the second assembly  218 , and the catheter operating member  280  are allowed to separate. 
     Also, a catheter assembly  210 A according to a third variation has a structure of collectively restrict separation of a first assembly  216  and a second assembly  218  (safety mechanism  260 A) by a cam unit  281  of a catheter operating member  280  as illustrated in  FIGS. 22A to 22C . The separation restricting mechanism  211 A is formed of a valve mechanism  250 A, the safety mechanism  260 A, and the cam unit  281  of the catheter operating member  280 . 
     In this case, the first assembly  216  (valve mechanism  250 A) is provided with an extending portion  253  including a locking hole  253   a  as in the second variation and is configured to catch a cam main body  284  by the locking hole  253   a . Accordingly, it is possible that the catheter assembly  210 A is not provided with a catch projection  252  and a catch hole  283  of the catheter operating member  280 . 
     In an initial state, the catheter assembly  210 A inserts the cam main body  284  in the locking hole  253   a  of the first assembly  216  and a cutout space  265  of the safety mechanism  260 A, and restricts the separation of the first assembly  216 , the safety mechanism  260 A, and the catheter operating member  280 . When a needle tip  15  of an inner needle  14  moves toward a proximal end than the cam main body  284  at the time of an inner needle retraction operation, the cam main body  284  becomes displaceable. As a result, the cam main body  284  may get out of the cutout space  265  and the locking hole  253   a , and the separation of the first assembly  216 , the safety mechanism  260 A, and the catheter operating member  280  is allowed. 
     As described above, the catheter assembly  210 A according to the third variation may also obtain an effect similar to that of the catheter assembly  210  according to the third embodiment. Especially, the catheter assembly  210 A is connected to both the first and second assemblies  216  and  218  by the cam main body  284  of the catheter operating member  280  in the inserted state (separation is restricted), so that a configuration may be made simple. 
     Fourth Embodiment 
     As illustrated in  FIGS. 23A to 24C , a catheter assembly  310  according to a fourth embodiment is different from catheter assemblies  10 ,  10 A,  110 ,  110 A,  210 , and  210 A in a structure that a catheter operating member  380  engages in a catheter hub  320  in an initial state. A separation restricting mechanism  311  is formed of the catheter hub  320  of a first assembly  316 , an inner needle  14  of a second assembly  318 , and a connecting unit  384  of the catheter operating member  380 . 
     The connecting unit  384  of the catheter operating member  380  is inserted in a hollow portion  325  of the catheter hub  320  and switchingly engaged with and disengaged from the catheter hub  320  on the basis of an inserted state and a non-inserted state of the inner needle  14  of the second assembly  318 . The connecting unit  384  includes a hanging plate  385  projecting downward from a lower surface on a proximal end side of a plate body  381  of the catheter operating member  380  and a connecting tube  386  projecting from the hanging plate  385  by a predetermined length. 
     The hanging plate  385  is firmly coupled to the lower surface of the plate body  381  of the catheter operating member  380  to arrange the connecting tube  386  at a predetermined height. The connecting tube  386  is firmly coupled to a distal end face  385   a  of the hanging plate  385 , and an insertion hole  386   a  in which the inner needle  14  is inserted is provided therein. The insertion hole  386   a  penetrates to a proximal end face  385   b  of the hanging plate  385 . 
     A pair (a plurality) of slits  387  communicated with the insertion hole  386   a  and vertically dividing the connecting tube  386 , and a locking flange  388  projecting radially outward from a body portion to be locked by the catheter hub  320  are provided on a distal end side of the connecting tube  386 . The distal end side of the connecting tube  386  divided by a pair of slits  387  may be shaped in a direction such that the divided portions come close to each other. As a result, when the engagement is released, the connecting tube  386  and the catheter hub  320  are easily separated. Note that the divided portions may extend in parallel to each other. In contrast, the catheter hub  320  is provided with a locking groove  326  that circulates in a circumferential direction on an inner surface forming the hollow portion  325 . 
     In the catheter operating member  380 , the inner needle  14  is inserted also in the insertion hole  386   a  of the connecting tube  386  in the inserted state in which the inner needle  14  is inserted in the catheter  12 . In this state, the divided portions on the distal end side of the connecting tube  386  are pushed by an outer peripheral surface of the inner needle  14  to be separated from each other, and the locking flange  388  at the distal end is caught by the locking groove  326 . As a result, the connecting tube  386  is inhibited from getting out of the catheter hub  320 , and movement of the catheter operating member  380  in a vertical direction or a width direction with respect to the first assembly  316  and the second assembly  318  including the inner needle  14  is restricted. 
     Therefore, as illustrated in  FIG. 24A , when the user advances the catheter operating member  380 , advancing operating force is transmitted to the first assembly  316  via the locking portion of the locking flange  388  and the locking groove  326 , and the hanging plate  385  and a proximal end of the catheter hub  320 . As a result, the first assembly  316  and the catheter operating member  380  may be advanced relative to the inner needle  14 . 
     As illustrated in  FIG. 24B , when the inner needle  14  moves toward the proximal end than the connecting tube  386  of the catheter operating member  380 , the divided portions of the connecting tube  386  come close to each other and locking of the locking flange  388  and the locking groove  326  is released. That is, as illustrated in  FIG. 24C , the separation of the first assembly  316  from the catheter operating member  380  is allowed on the basis of a fact that the inner needle  14  exits the catheter operating member  380  in the non-inserted state in which the inner needle  14  separates from the catheter  12 . As a result, the first assembly  316  may be indwelled in a satisfactory condition on a patient side. 
     As described above, the catheter assembly  310  according to the fourth embodiment may also obtain the effect similar to that of the catheter assemblies  10 ,  10 A,  110 ,  110 A,  210 , and  210 A. Especially, the catheter assembly  310  is such that the connecting unit  384  is directly connected to the inner needle  14  so as to be slidable in the catheter hub  320 , so that the engagement between the second assembly  318  and the catheter operating member  380  becomes simple. Note that the catheter assembly  310  is not limited to the above-described configuration, and for example, the first assembly  316  may be provided with the valve mechanism  50 . 
     As in a catheter assembly  310 A according to a fourth variation illustrated in  FIGS. 25A to 25C , a safety mechanism  360 A (auxiliary member) for accommodating a needle tip  15  of an inner needle  14  may also be added to the configuration of the catheter assembly  310  described above. That is, a separation restricting mechanism  311 A is formed of a catheter hub  320 A of a first assembly  316 , a safety mechanism  360 A of a second assembly  318 , and a connecting unit  384  of a catheter operating member  380 . 
     For example, the safety mechanism  360 A of the catheter assembly  310 A is formed into a tubular shape accommodated in an insertion hole  386   a  of the connecting unit  384  (connecting tube  386 ) of the catheter operating member  380 . Divided portions of the connecting tube  386  are pushed from inside by the safety mechanism  360 A in an inserted state in which the inner needle  14  is inserted in the catheter  12 , so that a locking flange  388  is caught by a locking groove  326 . Therefore, separation of the catheter hub  320 A, the safety mechanism  360 A, and the connecting unit  384  is restricted. 
     When the housing  30  and the inner needle  14  are moved in a proximal end direction, the vicinity of the needle tip  15  is caught by the safety mechanism  360 A (for example, a retaining member  68 ), and the safety mechanism  360 A is retracted. As a result, the safety mechanism  360 A separates from the connecting tube  386 , and in the separated state, re-exposure of the inner needle  14  is inhibited by an appropriate mechanism (for example, a shutter  65 ). In a non-inserted state, separation of the first assembly  316 , the second assembly  318 , and the catheter operating member  380  may be allowed as locking of the locking flange  388  and the locking groove  326  is released. 
     Fifth Embodiment 
     A catheter assembly  410  according to a fifth embodiment is configured such that a catheter operating member  480  is directly engaged with an inner needle  14  of a second assembly  418  so as to be slidable on a side closer to a proximal end than a catheter hub  20  as illustrated in  FIGS. 26 to 28C . A separation restricting mechanism  411  is formed of the catheter hub  20  of a first assembly  416 , the inner needle  14  of the second assembly  418 , and a connecting unit  484  of the catheter operating member  480 . 
     As illustrated in  FIGS. 26, 27 and 28A , the catheter operating member  480  is provided with the connecting unit  484  coupled to a proximal end of an operating plate  81  and accommodates the catheter hub  20  in an accommodating chamber  485  in the connecting unit  484  in an initial state. In a cross-sectional view orthogonal to an axial center of the connecting unit  484 , the connecting unit  484  is provided with an arch-like tubular wall  486  formed of an arc-shaped upper wall and side walls linearly extending downward from both ends in a circumferential direction of the upper wall (that is, having a semi-tubular shape as a whole). A lower side of the tubular wall  486  is formed in a flat shape parallel to an axial direction of the connecting unit  484  and is provided with an opening portion  488  communicated with the accommodating chamber  485 . 
     A length in the axial direction of the connecting unit  484  is somewhat longer than a length in the axial direction of the catheter hub  20  to which the valve mechanism  450  is attached. Both the catheter hub  20  and the valve mechanism  450  are accommodated in the accommodating chamber  485 . Note that this catheter assembly  410  is not provided with a safety mechanism. Therefore, although the valve mechanism  450  is formed of a valve main body  451  and a connector  455  (having no structure to catch the safety mechanism) having substantially the same functions as those of the valve main body  51  and the connector  55  of the first embodiment, the length in the axial direction thereof is slightly shorter than that of the other embodiments. Note that the valve mechanism  450  may also be formed only of the valve main body  451  (elastic member). 
     While an outer peripheral surface side of the tubular wall  486  of the connecting unit  484  is continuous with a constant outer diameter (dimension), an inner peripheral surface side thereof changes according to an outer shape of the catheter hub  20 . Specifically, a distal end side wall portion  486   a  bulges radially inward so that a distal end side accommodating chamber  485   a  is a small space, and a proximal end side wall portion  486   b  is formed to be thinner than the distal end side wall portion  486   a  so that a proximal end side accommodating chamber  485   b  is a large space. In this case, a lateral width of the distal end side accommodating chamber  485   a  is formed to be smaller than a diameter of a large-diameter portion  21  of the catheter hub  20 . Between the distal end side wall portion  486   a  and the proximal end side wall portion  486   b , an intermediate side wall portion  486   c  that increases the space in a tapered manner toward the proximal end direction is formed to form an intermediate side accommodating chamber  485   c.    
     In the initial state, the distal end side accommodating chamber  485   a  accommodates a small-diameter portion  23  of the catheter hub  20 , the intermediate side accommodating chamber  485   c  accommodates a transition portion  22  of the catheter hub  20 , and the proximal end side accommodating chamber  485   b  accommodates the large-diameter portion  21  of the catheter hub  20 . The inner peripheral surfaces of the distal end side wall portion  486   a , the proximal end side wall portion  486   b , and the intermediate side wall portion  486   c  are designed to have dimensions separated to a certain degree radially outward from the outer peripheral surface of the catheter hub  20  so as to accommodate the catheter hub  20  in a non-contact manner within the accommodating chamber  485 . 
     In addition, while the connecting unit  484  opens a distal end of the accommodating chamber  485 , this closes a proximal end side of the accommodating chamber  485  by a blocking wall  487  (wall portion) continuous to the semi-tubular proximal end side wall portion  486   b . An inner needle through hole  487   a  through which the inner needle  14  may penetrate is provided in a predetermined position of the blocking wall  487 . That is, in the initial state, the blocking wall  487  is directly connected to the inner needle  14 . In the initial state, the blocking wall  487  is arranged on a distal end side of a needle holding member  40  and comes into contact with a proximal end of the valve mechanism  450  by advancing operating force of a user to push out the first assembly  416 . 
     Also, because the intermediate side wall portion  486   c  is formed into a tapered shape, this faces a distal end side of the transition portion  22  of the catheter hub  20 . Therefore, the intermediate side wall portion  486   c  comes into contact with the transition portion  22  of the catheter hub  20  and retracts the first assembly  416  with a retraction operating force by the user transmitted. 
     The catheter assembly  410  described above is such that the inner needle  14  is also inserted in the connecting unit  484  of the catheter operating member  480  in an inserted state in which the inner needle  14  is inserted in the catheter  12 , thereby restricting separation of the catheter hub  20 , the inner needle  14 , and the connecting unit  484  of the catheter operating member  480 . That is, the catheter hub  20  is restricted from moving in a direction other than the axial direction of the inner needle  14  by the inner needle  14  inserted therein, and because this is in the accommodating chamber  485 , relative movement (movement in the axial direction and in a separating direction) with respect to the catheter operating member  480  is restricted. 
     When the user performs an advancement operation of the catheter operating member  480  in a distal end direction, the blocking wall  487  pushes the valve mechanism  450  to relatively advance the first assembly  416  with respect to the inner needle  14 . On the other hand, when the user performs a retraction operation of the catheter operating member  480  in the proximal end direction, the intermediate side wall portion  486   c  pushes the catheter hub  20  in the proximal end direction to relatively retract the first assembly  416  with respect to the inner needle  14 . Also, when the catheter operating member  480  advances, the tubular wall  486  comes into contact with a supporting member  45 , so that the supporting member  45  may be satisfactory rotated. 
     Then, as illustrated in  FIG. 28B , when the inner needle  14  exits the connecting unit  484  in the proximal end direction (that is, in a non-inserted state), the catheter operating member  480  is in a free state with respect to the inner needle  14 . Separation of the catheter hub  20  originally accommodated in a non-contact manner with the catheter operating member  480  is also allowed. Therefore, as illustrated in  FIG. 28C , the first assembly  416  is such that the catheter hub  20  easily exits the opening portion  488  of the connecting unit  484  downward. After the catheter hub  20  separates from the catheter operating member  480 , an operator removes the valve mechanism  450  from the catheter hub  20 . As a result, the catheter  12  and the catheter hub  20  are indwelled in a satisfactory condition on a patient side. 
     As described above, the catheter assembly  410  (separation restricting mechanism  411 ) according to the fifth embodiment may also obtain the effect similar to that of the catheter assemblies  10 ,  10 A,  110 ,  110 A,  210 ,  210 A,  310 , and  310 A. Especially, the catheter assembly  410  has a simple configuration in which the inner needle  14  is slidably connected to the connecting unit  484  in a proximal end position of the catheter hub  20 . Therefore, reduction in manufacturing cost and the like are further promoted. 
     In addition, because the connecting unit  484  covers an upper portion and a side portion of the catheter hub  20 , it is possible to inhibit the catheter hub  20  and the housing  30  from coming into contact with each other when the catheter operating member  480  moves, thereby suppressing the catheter hub  20  from shaking. Furthermore, the connecting unit  484  may reduce a chance that the user touches and contaminates the catheter hub  20 . Also, because an inner peripheral surface of the connecting unit  484  is separated from the outer peripheral surface of the catheter hub  20  and connecting strength is zero, when the inner needle  14  is separated, the catheter hub  20  may be separated from the catheter operating member  480  without force. Furthermore, the catheter assembly  410  is such that the inner needle  14  is inserted in the valve main body  451  and the connector  455 , thereby inhibiting the inner needle  14  and the first assembly  416  from shaking. 
     Note that it is a matter of course that the catheter assembly  410  may also adopt various configurations. For example, although the inner peripheral surface of the connecting unit  484  is separated radially from the outer peripheral surface of the catheter hub  20  in the above-described embodiment, it is also possible to configure such that the inner peripheral surface of the connecting unit  484  comes into contact with the catheter hub  20  to apply some frictional force. 
     Also, for example, the valve mechanism  450  (valve main body  451 ) may be provided inside the catheter hub  20 . Furthermore, on a side surface of the catheter hub  20 , an extension tube (including a side hole in which the extension tube may be attached) or a port to which an infusion set may be connected may be provided. Furthermore, the catheter assembly  410  may have a safety mechanism as described in the other embodiments. For example, the safety mechanism may engage with the first assembly  416  (refer also to a fifth variation described later) or the catheter operating member  480  in the initial state and engage with the needle tip  15  to separate as the inner needle  14  retracts. 
     A catheter assembly  410 A according to a fifth variation illustrated in  FIGS. 29A and 29B  is configured to surround an entire circumference of a valve mechanism  50  by a ring-shaped connecting unit  490  of a catheter operating member  480 A. Also, the catheter assembly  410 A is provided with the valve mechanism  50  and a safety mechanism  60  as in the first embodiment. A separation restricting mechanism  411 A is formed of the valve mechanism  50  of a first assembly  416 , the safety mechanism  60  of a second assembly  418 , and the connecting unit  490  of the catheter operating member  480 A. 
     The connecting unit  490  of the catheter operating member  480 A has a certain thickness in a longitudinal direction of the catheter operating member  480 A. The connecting unit  490  is provided with an arranging hole  491  penetrating a distal end face  490   a  and a proximal end face  490   b ; the arranging hole  491  in which the valve mechanism  50  is arranged is formed so as to be smaller than an outer annular convex portion  58  of the valve mechanism  50  and an outer tube  71  in diameter (refer also to  FIG. 3 ). Because the arranging hole  491  penetrates through the valve mechanism  50  between the catheter hub  20  and the safety mechanism  60 , relative displacement of the connecting unit  490  in vertical and width directions with respect to the first and second assemblies  416  and  418  is restricted. 
     When the catheter operating member  480 A advances, the connecting unit  490  comes into contact with the valve mechanism  50  to transmit advancing operating force to the first assembly  416  and the safety mechanism  60 . When retracting, the connecting unit  490  comes into contact with the outer tube  71 , and transmits a retraction operating force to the first assembly  416  and the safety mechanism  60 . After an inner needle  14  is removed from a catheter  12  and the valve mechanism  50  and the safety mechanism  60  are separated from each other, the connecting unit  490  is removed from a proximal end of the valve mechanism  50 , and the first assembly  416  and the catheter operating member  480 A are easily separated. 
     As described above, the catheter assembly  410 A according to the fifth variation may also obtain the effect similar to that of the catheter assemblies  10 ,  10 A,  110 ,  110 A,  210 ,  210 A,  310 ,  310 A, and  410 . Especially, the catheter assembly  410 A has a simple structure in which the connecting unit  490  does not cover a side portion of the catheter hub  20 , and work efficiency and the like at the time of manufacturing are further improved. 
     In a catheter assembly  410 B according to a sixth variation illustrated in  FIGS. 30A to 30C , as in the catheter assembly  410 A according to the fifth variation, a connecting unit  492  of a catheter operating member  480 B is formed into a ring shape projecting to a lower surface of the plate body  481 . The connecting unit  492  includes an engagement hole  493  penetrating through a distal end face  492   a  and a proximal end face  492   b  in which an inner needle  14  is slidably inserted and is directly connected so as to be slidable with respect to the inner needle  14  in an initial state. Also, in the initial state, the connecting unit  492  is arranged so as to be contactable with a proximal end of a catheter hub  20  of a first assembly  416 , thereby transmitting advancing operating force of the catheter operating member  480 B to the catheter hub  20  of the first assembly  416 . 
     The catheter operating member  480 B is provided with an operating projection  494  in a position away from the connecting unit  492  in a distal direction by a predetermined interval (for example, a length in an axial length of the catheter hub  20 ). The operating projection  494  interposes the catheter hub  20  in an axial direction in cooperation with the distal end face  492   a  of the connecting unit  492  and transmits a retraction operating force of the catheter operating member  480 B. The operating projection  494  may interpose a flange  24  between the same and the connecting unit  492 . 
     Therefore, in an inserted state in which the inner needle  14  is inserted in the catheter  12 , the inner needle  14  is also inserted in the connecting unit  492  of the catheter operating member  480 B, restricting separation of the catheter hub  20 , the inner needle  14 , and the connecting unit  492  of the catheter operating member  480 B. When the catheter operating member  480 B advances relative to the inner needle  14  and the inner needle  14  exits the engagement hole  493  of the connecting unit  492  (that is, in a non-inserted state), the separation of the catheter hub  20 , the inner needle  14 , and the catheter operating member  480 B is allowed. 
     As described above, the catheter assembly  410 B (separation restricting mechanism  411 B) according to the sixth variation may also obtain the effect similar to that of the catheter assemblies  10 ,  10 A,  110 ,  110 A,  210 ,  210 A,  310 ,  310 A,  410 , and  410 A. Note that the catheter assembly  410 B may also adopt various configurations and, for example, the first assembly  416  may include a valve mechanism  450 . 
     The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications may be made without departing from the spirit of the present invention.