An intermediate shaft is provided which connects a steering shaft and a steering gear mechanism together via a universal joint, a shoulder bolt is provided which fastens one of yokes of the universal joint and a shaft portion of the intermediate shaft and on which a small diameter portion and a large diameter portion which are adapted to be brought into engagement with an outer circumferential surface of the shaft portion are formed sequentially from a distal end portion side, and the intermediate shaft has a bolt engagement recess portion which is formed on an outer circumferential surface of the shaft portion in such a manner as to extend in a direction which intersects an axial direction and which is adapted to be brought into engagement with the large diameter portion of the shoulder bolt and a dislocation preventive projecting portion which is formed on an outer circumferential surface of an end portion thereof, whereby a temporary fastening is implemented by bringing the small diameter portion of the shoulder bolt into engagement with an outer circumferential surface which lies adjacent to the bolt engagement recess portion, and a final fastening is implemented by bringing the large diameter portion of the shoulder bolt into engagement with the bolt engagement recess portion.