PROBLEM TO BE SOLVED: To form arbitrary, fine recessed shapes on an outer surface of a needle.SOLUTION: A recessed part having an inner diameter or an inner dimension of less than 120 μm is formed on an outer surface by irradiating the outer surface of an injection needle 7, a puncture needle 7, a blood sampling needle 7, and the other needle 7 with laser beams L. A laser beam processing machine 1 used for forming the recessed part includes: a laser beam irradiating device for emitting the laser beams for forming the recessed part having the inner diameter or the inner dimension of less than 120 μm at a place where the recessed part is formed, for example, on the outer surface of the needle； an axial direction displacing mechanism 2, 4 for relatively displacing an optical axis of the laser beams output from the laser beam irradiating device in an axial direction of the needle relative to the outer surface of the needle； and a rotational direction displacing mechanism 2, 3 for relatively displacing the optical axis of the laser beams output from the laser beam irradiating device in a rotational direction around the axis of the needle relative to the outer surface of the needle.SELECTED DRAWING: Figure 1【課題】針の外面に任意の微細な凹形状を形成できるようにする。【解決手段】注射針７や穿刺針７、採血針７その他の針７の外面にレーザ光Ｌを照射することで、当該外面に内径若しくは内寸が１２０μｍ未満の凹部を形成する。そのためのレーザ加工機１は、例えば、針の外面における凹部を形成するべき箇所に内径若しくは内寸が１２０μｍ未満の凹部を形成するレーザ光を照射するレーザ光照射装置と、レーザ光照射装置から出射するレーザ光の光軸を針の外面に対し針の軸方向に沿って相対的に変位させる軸方向変位機構２、４と、レーザ光照射装置から出射するレーザ光の光軸を針の外面に対し針の軸回りの回転方向に沿って相対的に変位させる回転方向変位機構２，３とを具備する。【選択図】図１
