An endoscopic treatment tool includes a flexible sheath; an operating member inserted to the sheath so as to freely advance and retract; a treatment section disposed at the distal end of the operating member that protrudes and retracts from the sheath; and an operator section connected to the proximal end of the operating member including a sliding member which makes the operating member advance and retract. The endoscopic treatment tool includes the operating member consisting of a member which increases its rigidity by compression, and a member which compresses the operating member. Therefore a sufficient incision or excision is achieved relative to the distance of movement of the treatment tool by preventing a deflection of the flexible tube when in use.