PROBLEM TO BE SOLVED: To stabilize behavior of a deflection part of a distal end movable catheter.SOLUTION: An operation part provided at a proximal end of a catheter comprises: a rotary operation member rotatably held while being sandwiched by first and second holding parts 42a, 42b； and rotation regulation means 6, 7 for regulating the rotation of the rotary operation member by releasably pressing substantially central portions of the first and second holding parts in a direction of approaching each other. The rotary operation member comprises: a first rotary operation member 32 in which an arcuate groove is formed； first and second movable members 34a, 34b movably attached along the arcuate groove； and a second rotary operation member 33 integrally attached to the first rotary operation member in a state that the first and second movable members are accommodated in an interior space defined between an inner face of the first rotary operation member and itself. A support member whose distal end face comes into contact with an inner face of the second rotary operation member is provided on the inner face of the first rotary operation member.SELECTED DRAWING: Figure 21【課題】先端可動カテーテルの偏向部の挙動を安定させる。【解決手段】カテーテルの近位端に設けられた操作部は、第１および第２保持部４２ａ，４２ｂに挟み込まれた状態で、回転自在に保持された回転操作部材と、第１および第２保持部の略中央部分を互いに近接する方向に解除可能に押圧して、回転操作部材の回転を規制する回転規制手段６，７とを備え、回転操作部材は、円弧状溝が形成された第１回転操作部材３２と、円弧状溝に沿って移動可能に取り付けられた第１および第２可動部材３４ａ，３４ｂと、第１回転操作部材の内面との間に画成される内部空間に第１および第２可動部材が収容された状態で、該第１回転操作部材に一体的に取り付けられる第２回転操作部材３３とを備え、第１回転操作部材の内面に、その先端面が第２回転操作部材の内面に当接する支柱部材を設けた。【選択図】図２１
