The treatment instrument for endoscope has a guide pipe and a guide sheath. The guide pipe allows observation of the distal end side of the distal end of the insertion portion and the distal end side of the first distal end with the observation optical system of the endoscope through the first distal end, or makes the distal end of the insertion portion protrude from the first distal end. In this state, the insertion portion is inserted into the insertion portion so that the distal end side of the insertion portion can be observed with the observation optical system. The guide sheath has an inner diameter that allows the insertion portion to pass through the inside of the guide pipe so that the tip of the insertion portion can protrude from the second tip, and the guide pipe can project the second tip from the first tip of the guide pipe. Is inserted inside.内視鏡用処置具はガイドパイプとガイドシースとを有する。ガイドパイプは、その第１先端を通して内視鏡の観察光学系で挿入部の先端の先端側かつ第１先端の先端側を観察可能、又は、挿入部の先端を第１先端に対して突出させた状態で挿入部の先端の先端側を観察光学系で観察可能に挿入部をその内側に挿通させる。ガイドシースは、挿入部の先端をその第２先端に対して突出可能に挿入部をその内側に挿通させる内径を有し、ガイドパイプの第１先端に対して第２先端を突出可能にガイドパイプの内側に挿通される。
