This endoscope treatment instrument, the sheath is configured to be inserted through a channel of an endoscope, a treatment portion provided at the distal end of the sheath, the tip part together is movably inserted in the sheath It is connected to the treatment portion, and the elongate member to operate the treatment portion by advancing and retracting relative to the sheath, comprising an operation section provided on the proximal end of the sheath and the operating portion is operated, which is connected to the sheath a unit main body, the operation portion movably provided along the axial direction of the sheath relative to the body, a slider base end portion of the elongated member is connected, provided in the operation portion main body, the slider in the position of the slider and an a constant force spring portion that urges toward the base end side with a constant force regardless.本内視鏡処置具は、内視鏡のチャンネルに挿通可能に構成されたシースと、シースの先端部に設けられた処置部と、シースに進退可能に挿通されるとともに先端部が処置部に接続され、シースに対して進退することで処置部を動作させる長尺部材と、シースの基端部に設けられた操作部と、を備え、操作部は、シースに接続された操作部本体と、操作部本体に対してシースの軸線方向に沿って移動可能に設けられ、長尺部材の基端部が接続されたスライダと、操作部本体に設けられ、スライダをスライダの位置によらず一定の力で基端側に向かって付勢する定荷重バネ部と、を有する。
