The treatment tool insertion tool 2 is a treatment tool insertion tool that is attached to the insertion portion 11 of the endoscope 1 that is inserted into the subject and allows the treatment tool 41 to be inserted into the insertion portion 11. The treatment tool 41 that can be connected to the attachment portion 33 for attaching the main body portion 50 to the insertion portion 11 and the treatment instrument insertion port 22 of the endoscope 1 and extends from the main body portion 50 is connected to the treatment instrument insertion port 22. The guide part 32 for guiding into the insertion part 11 via the body part 50 and the treatment tool 41 inserted in the body part 50 by being elastically deformed at least partially can be fixed. In the fixed state in which the instrument 41 is fixed, the treatment instrument 41 has an operation member 54 for performing an operation of advancing and retracting along the axial direction and rotating around the axis.処置具挿通具２は、被検体内に挿入される内視鏡１の挿入部１１に取り付けられ、挿入部１１内に処置具４１を挿通させるための処置具挿通具であって、 本体部５０と、本体部５０を挿入部１１に取り付けるための取付部３３と、内視鏡１の処置具挿入口２２に接続可能で、本体部５０から延出した処置具４１を、処置具挿入口２２を介して挿入部１１内に案内するための案内部３２と、本体部５０に設けられ、少なくとも一部が弾性変形することにより本体部５０内に挿通された処置具４１を固定可能で、処置具４１を固定した固定状態において処置具４１の軸方向に沿った進退及び軸回りの回動の操作を行うための操作部材５４を有する。
