Abstract: This safety headed cotter pin having an annular holding device comprises a substantially cylindrical body, a head formed integrally with this body, an annular device adapted to prevent any undesired removal of the cotter pin and retaining means comprising a stop-forming element rigid with the head and adapted to cooperate with at least one of the end portions of the annular device in order to limit the permissible movement of this device in the direction away from its closed position, this cotter pin being intended notably for use in various farming vehicles and machines, for example for keeping mechanical component elements on parts such as shafts and the like.