PROBLEM TO BE SOLVED: To provide a bending treatment instrument which can freely bend an end part to which a device is fitted independently of a soft endoscope, can prevent twist of the device when inserted in the soft endoscope, and has no risk to cause problems to arrangements and movements of people and objects when rotating the soft endoscope.SOLUTION: There are provided: an operation part which performs bending motions of a bent part 4 where a treatment member is fitted to an end, opening/closing operation of forceps as a treatment member, and projecting/receding operation of a scalpel as a treatment member； a sheath/wire part 5 transmitting operation of the operation part； and a shaft fixing means 100 blocking rotation of the sheath/wire part around the shaft. The shaft fixing means is provided with a shaft fixing part where a groove engaged with an engaging projection fixed to the sheath/wire part is formed, which allows movements of the sheath/wire part in an axial direction and blocks rotation around the shaft. An end part on the bent part side of the shaft fixing means is curved in the way that a rotation center axis of the soft endoscope is parallel to the shaft fixing means when the shaft fixing means is held by an endoscope channel.SELECTED DRAWING: Figure 19【課題】デバイスが取り付けられた先端部を軟性内視鏡と独立して自由に屈曲させることができ、軟性内視鏡内に挿入する際のデバイスの捩じれを防止することができ、軟性内視鏡を旋回させる際の人や物の配置や動きに支障を来すおそれがない屈曲処置具を提供する。【解決手段】先端に処置部材が取り付けられた屈曲部４の屈曲動作、処置部材としての鉗子の開閉動作および処置部材としてのメスの出没動作を行う操作部と、操作部の操作を伝達するシース・ワイヤ部５と、シース・ワイヤ部の軸回りの回転を阻止する軸固定手段１００とを備え、軸固定手段は、シース・ワイヤ部に固定された係合突起と係合する溝が形成されて、シース・ワイヤ部の軸方向への移動を許容し、軸回りの回転を阻止する軸固定部とを備え、軸固定手段の屈曲部側の端部は、軸固定手段を内視鏡チャンネルに保持させた際に、軟性内視鏡の旋回中心軸と軸固定手段とが平行になるように湾曲している．【選択図】図１９
