To provide a method of manufacturing a distal end section of a medical treatment tool, the method being capable of manufacturing a distal end section of a medical treatment tool with less steps, which medical treatment tool has step-free surfaces and exhibits an excellent rotation performance.SOLUTION: A method of manufacturing a distal end section 1 of a medical treatment tool comprises: an intermediate member placement step of placing arm portions 22a, 22b of cup members 20a, 20b inside a slit 11； a pin member placement step of inserting a pin member 40 through through-holes 12, 13, 221a, 221b and placing the pin member such that an end face 41a of a dish part 41 is located below a lower opening end of the through-hole 13 and a to-be-processed part 42 protrudes from an upper opening end of the through-hole 12； a swaging step of applying a swaging process in such a manner that the to-be-processed part 42 is depressed to cause plastic deformation thereon, a cover member 10 is flexed to reduce the width of the slit 11, and a dish hole 14 is filled with the plastically deformed to-be-processed part 42； and a dish part adhesion step of undoing the width of the slit 11 back to the original width by the resilience of the cover member 10 to tightly adhere the dish part 41 to a dish hole 15.SELECTED DRAWING: Figure 1【課題】回転性能が高く、かつ表面に段差のない医療用処置具の先端部を少ない工程で製造することができる医療用処置具の先端部の製造方法を提供すること。【解決手段】医療用処置具の先端部１の製造方法は、スリット１１内にカップ部材２０ａ，２０ｂのアーム部２２ａ，２２ｂを配置する中間部材配置工程と、ピン部材４０を貫通孔１２，１３，２２１ａ，２２１ｂに挿通し、皿部４１の端面４１ａが貫通孔１３の下側開口端よりも下位に位置し、かつ加工部４２が貫通孔１２の上側開口端から突出するように配置するピン部材配置工程と、加工部４２を押圧して塑性変形させ、スリット１１の幅が縮まるようにカバー部材１０を撓ませ、塑性変形した加工部４２によって皿孔１４を埋めるようにカシメ加工を行うカシメ加工工程と、カバー部材１０の弾性によってスリット１１の幅を元の幅へと広げ、皿孔１５に皿部４１を密着させる皿部密着工程とを含む。【選択図】図１
