PROBLEM TO BE SOLVED: To provide a bent part of a treatment tool for an endoscope, which is easily assembled and has excellent strength even in an extremely thin diameter inserted into the insertion channel of the treatment tool for the endoscope.SOLUTION: A convex joint ring 31 with an exterior shape formed into a convex lens shape and a concave joint ring 32 with an external shape formed into a concave lens shape are alternately arranged in a straight line matching respective axis line positions into a state abutting on each other. A curvature radius of the convex part of the convex joint ring 31 is formed smaller than a curvature radius of the concave part of the concave joint ring 32. In the convex joint ring 31 and concave joint ring 32, respectively, main passage holes 33, through which a tip end treatment part operation wire 13 for remotely operating a tip end treatment part 2 passes, are formed penetrating so as to be connected straight, and sub-passage holes 34, through which a curved operation wire 15 passes, are formed penetrating at positions deviated from respective axis line positions of the respective joint rings 31, 32 so as to be connected straight.COPYRIGHT: (C)2012,JPO&INPIT【課題】内視鏡の処置具挿通チャンネルに通される極細の径であっても、組み立てが容易でしかも優れた強度を保有することができる内視鏡用処置具の湾曲部を提供すること。【解決手段】外面形状が凸レンズ形に形成された凸形関節輪31と外面形状が凹レンズ形に形成された凹形関節輪32とが、互いに当接する状態に軸線位置を合わせて直列に交互に配置されて、凸形関節輪31の凸部の曲率半径が凹形関節輪32の凹部の曲率半径より小さく形成され、凸形関節輪31と凹形関節輪32には各々、先端処置部2を遠隔操作するための先端処置部操作ワイヤ13が通過する主通過孔33が、真っ直ぐに連なるように貫通形成されると共に、湾曲操作ワイヤ15が通過する副通過孔34が、真っ直ぐに連なるように各関節輪31,32の軸線位置から偏心した位置に貫通形成されている。【選択図】 図1
