PROBLEM TO BE SOLVED: To provide an attaching method of a ring in a needle assembly, with which a projection length can be settled at a stipulated value and an yield can be improved.SOLUTION: A first ring 31 is disposed on the outer circumference of an installation part 13, a second ring 41 is disposed on the outer circumference of the first ring 31, an inner needle 21 is inserted to a trocar 61, the proximal end of the trocar 61 is abutted on the second ring 41, the second ring 41 is moved in the axial direction of the inner needle 21 together with the trocar 61, and a projection length L of the projection from the distal end of the trocar 61 of an inclined surface 22 provided on the distal end of the inner needle 21 is adjusted to the stipulated value. Then, the first ring 31 as a light absorption part is irradiated with light through the second ring 41 and the first ring 31 and the second ring 41 are optically welded.COPYRIGHT: (C)2013,JPO&INPIT【課題】突出長を規定値に収めて歩留まりを向上させることのできる針組立体におけるリングの取付方法を提供する。【解決手段】第1のリング31を設置部13の外周に配置し、第2のリング41を第1のリング31の外周に配置し、内針21を外套針61に挿通して外套針61の基端を第2のリング41に突き当て、第2のリング41を外套針61ととも内針21の軸方向へ移動させて内針21の先端に設けられた傾斜面22が外套針61の先端から突出する突出長Lを規定値に調整した後、第2のリング41を介して光吸収部位としての第2のリング31に光を照射して第1のリング31と第2のリング41とを光溶着する。【選択図】図3
