The catheter has a pressure chamber defined by a proximal seal and a distal seal, and an inner tubular member and an outer tubular member. An actuator member movable between the first position and the second position is disposed in the pressure chamber. The fluid introduced into the pressure chamber applies a force to the actuator member and moves the actuator member toward the second position. The locking mechanism disposed between the inner tubular member and the outer tubular member has an engaged state that prevents the outer tubular member from moving relative to the inner tubular member, and a disengaged state that allows the outer tubular member to move. Has a latch. The latch shifts to the disengaged state when the actuator member moves to the second position. When the actuator member is in the second position and the latch is in the disengaged state, the fluid introduced into the pressure chamber from the fluid flow port applies a force to the proximal seal and biases the outer tubular member proximally. [Selection] Figure 9カテーテルは、基端シール及び末端シールと、内側管状部材及び外側管状部材とによって画定される圧力チャンバを有する。第１位置と第２位置との間で移動可能なアクチュエータ部材は圧力チャンバ内に配置する。圧力チャンバ内に導入する流体はアクチュエータ部材に力を加え、アクチュエータ部材を第２位置に向けて移動する。内側管状部材と外側管状部材との間に配置したロック機構は、外側管状部材が内側管状部材に対して移動するのを阻止する係合状態、及び外側管状部材を移動可能にする離脱状態をとるラッチを有する。ラッチは、アクチュエータ部材が第２位置に移動するとき離脱状態にシフトする。アクチュエータ部材が第２位置に、ラッチが離脱状態にあるとき、流体フローポートから圧力チャンバ内に導入される流体は力を基端シールに加え、外側管状部材を基端方向に押圧偏倚する。【選択図】図９
