To provide a medical hollow needle assembly which is increased in joint strength of a hollow needle to an outer cylindrical body, relative to a tensile load, and a method of manufacturing a hollow needle.SOLUTION: A medical hollow needle assembly 1 includes an outer cylindrical body 5 including a through-hole 5a, a hollow needle 3 having an outer peripheral surface partially including an outer reduced-diameter surface 6 having a diameter reduced toward a distal end side, and having a proximal end side disposed in the through-hole 5a, and an inner cylindrical body 7 including an insertion hole 7c through which the hollow needle is inserted, the inner cylindrical body being disposed between the hollow needle and the inner peripheral surface of the through-hole, and joining the outer cylindrical body and the hollow needle. The insertion hole of the inner cylindrical body is provided with an inner reduced-diameter surface 9 reduced in diameter toward the distal end side, and engaging the outer reduced-diameter surface of the hollow needle. A method of manufacturing a hollow needle includes a pressing step of punching out a plate body having a predetermined shape from a metal plate, and rolling the plate body to be molded into a tubular shape, and a joining step of joining a seam portion of the plate body having been molded into the tubular shape. A surface of the plate body is roughened in the pressing step, to provide a roughened portion at least partially on an outer peripheral surface of a portion joined to the inner peripheral surface of the cylindrical body of the hollow needle.SELECTED DRAWING: Figure 2【課題】引張り荷重に対する中空針の外筒体への接合強度が高められた医療用の中空針組立体および中空針の製造方法を提供する。【解決手段】貫通孔５ａを備えた外筒体５と、先端側に向けて縮径する縮径外面６を外周面の一部に備え、基端側が貫通孔に配置される中空針３と、中空針が挿通される挿通孔７ｃを備え、中空針と貫通孔の内周面との間に配置されて外筒体と中空針とを接合する内筒体７とを有し、内筒体の挿通孔には、先端側に向けて縮径し、中空針の縮径外面に係合する縮径内面９が設けられる、中空針組立体１。金属板から所定形状の板状体を打ち抜き、板状体を丸めて管状に成型するプレス加工工程と、管状に成型された板状体の継ぎ目部分を接合する接合工程とを有し、プレス加工工程において板状体の表面に粗面加工を施して、中空針の筒体の内周面に接合される部位の外周面の少なく
