When a biotissue is sutured using a curved medical suture needle, the penetration resistance becomes uniform.In a bending method, a straight needle-shaped material A which has a thickness decreased from a body portion 1 to a needle point 2 is inserted between a roller 11 having a processing surface 11a and a belt 12 wound around the roller 11 via a separating member 21, and then the roller 11 is rotated and the belt 12 is winded, thereby pressing and curving the straight needle-shaped material onto the processing surface 11a. In a suture needle B, a portion of a tip side including the needle point 2 is formed as a non-restricted portion which is not restricted by the processing surface 11a of the roller 11, and a portion except for the non-restricted portion is formed as a curved portion which is bent along the processing surface 11a of the roller 11.