PROBLEM TO BE SOLVED: To provide a manufacturing method of an osteosynthesis material for preferably manufacturing an osteosynthesis material 11 which does not have a head, includes a screw 11a over substantially the entire length of an outer peripheral surface of the osteosynthesis material 11, and includes a hole 11b1 (11b) for inserting a predetermined fastening tool over substantially the entire length of the osteosynthesis material 11 along a central axis L of the osteosynthesis material 11.SOLUTION: A preform 1 made of a crystalline thermoplastic polymer material is installed in a female molding die 2a on an inner peripheral surface of which a spiral groove 21a corresponding to a screw 11a formed on an outer peripheral surface of an osteosynthesis material 11 is formed, a male molding die 2b which is formed in a shape corresponding to a hole 11b formed along a central axis L of the osteosynthesis material 11 is rotated while pushing-in the die along the central axis L of the preform 1 (same as the central axis L of the osteosynthesis material 11), by which the preform 1 is rotated together with the die, the preform 1 is compressed in an axial direction of the preform 1 and expanded radially outward with respect to the central axis L, and the screw 11a and the hole 11b are formed respectively on the outer peripheral surface and along the central axis L of the preform 1.
