PROBLEM TO BE SOLVED: To provide a treatment instrument capable of performing treatment while minimizing the number of holes to be formed in an abdominal wall, and smoothly performing cooperative operations of a plurality of treatment parts.SOLUTION: A treatment instrument 2 includes a support part 15 formed in a shaft-like shape, a treatment part 20 provided at a distal end of the support part for performing treatment, and an assistance part 41 provided at a distal end of the support part for assisting an operation of the treatment part at the time of treatment. The assistance part includes a treatment assistance part 35 that can be moved between a first position R1 close to the treatment part and a second position moved from the first position in a direction intersecting with a longitudinal axis C1 of the support part so as to be away from the treatment part, a drive part 67 for moving the assistance part of the treatment assistance part, an operation detection part 55 for detecting an amount of movement of the support part inserted into an introduction tool 3 with respect to the introduction tool, and an orientation of the support part, an operation part 65 provided at a proximal end of the support part, and a control part 80 for controlling the drive part based on the result of detection by the operation detection part.SELECTED DRAWING: Figure 1【課題】腹壁に形成する孔の数を最小限に抑えて処置をするとともに、複数の処置部の連携動作を円滑に行うことができる処置具を提供する。【解決手段】処置具２は、軸状に形成された支持部１５と、支持部の遠位端部に設けられ、処置を行うための処置部２０と、支持部の遠位端部に設けられ、処置時に処置部の動作を支援するための支援部４１を有し、支援部が、処置部に接近した第一の位置Ｒ１と、処置部から離間するように支持部の長手軸Ｃ１に交差する方向に第一の位置から移動した第二の位置との間で移動可能な処置支援部３５と、処置支援部の支援部を移動させる駆動部６７と、導入具３に挿通される支持部の導入具に対する移動量、及び支持部の向きを検出する操作検出部５５と、支持部の近位端部に設けられた操作部６５と、操作検出部の検出結果に基づいて駆動部を制御する制御部８０とを備える。【選択図】図１
