PURPOSE: To reduce the number of process and the cost by forming flat parts and thread relief grooves at the needle root part by a plastic working method and forming continuously an approximately triangular slit, etc., with a laser beam, etc.

CONSTITUTION: When, for example, a suture needle A is a needle which is used to suture intestines, the needle material 1 of 0.6 is used. At the 1st stage, the needle root part 1a of the needle material 1 is deformed plastically in flat with a press or a forging process and simultaneously the thread relief grooves 3 are formed at the approximate middle in the axial direction of the needle root part 1a and on both sides of the direction of depth. Next, at the 2nd stage, a notch 4, a thread inlet of about 0.1mm wide, preferably ≤0.1mm and a triangular slit 2 with a base length of 0.4mm are formed by cutting out. Then, at the 2nd stage, the notch 4, the thread inlet 5 and the slit 2 are cut out by moving relatively while irradiating the needle root part 1a which is provided with the thread inlet 3 and is formed flatly with the laser beam or an electron beam or while discharging between the needle material 1 and an electrical discharging wire. Thus, slit columns 6 can be formed.