PROBLEM TO BE SOLVED: To provide a method of manufacturing an endoscopic treatment instrument to which an operation wire and a wire-made treatment device having a large difference in the outer diameters can be jointed without causing ununiformity in the jointing strength and deterioration of the product performance.SOLUTION: An endoscopic treatment instrument 1 comprises: a metallic operation wire 22； a metallic snare 23 formed by bundling an end part of the metallic wire and having a proximal end part 234 with a smaller diameter than the operation wire 22； and a metallic connection member 24 arranged to cover the proximal end part 234 of the snare 23. The connection member 24 is caulkingly jointed to the proximal end part 234 of the snare 23. An end surface of the operation wire 22, an end surface of the proximal end part 234 of the snare 23, and an end surface of the connection member 24 continuing thereto are abutted together and jointed by upset resistance welding.SELECTED DRAWING: Figure 3【課題】接合強度のばらつきや製品性能の低下を招くことなく、外径差の大きい操作ワイヤおよびワイヤ処置具を接合することができる内視鏡用処置具の製造方法およびそれにより製造された内視鏡用処置具を提供すること。【解決手段】内視鏡用処置具１は、金属製の操作ワイヤ２２と、金属ワイヤの端部を束ねて形成されており、操作ワイヤ２２よりも小径の基端部２３４を有する金属製のスネア２３と、スネア２３の基端部２３４を覆うように配置された金属製の連結部材２４と、連結部材２４は、スネア２３の基端部２３４にカシメ接合されており、操作ワイヤ２２の端面と、スネア２３の基端部２３４の端面およびそれに連なる連結部材２４の端面とは、互いに突き合わされた状態で、アップセット抵抗溶接により接合されている。【選択図】図３
