A cam sprocket according to the present invention includes a ring-shaped plate portion having external teeth along its outer circumference; a circular plate portion that is disposed at the radially inner region substantially parallel to the ring-shaped plate portion and at a level difference in axial direction to the ring-shaped plate portion, the circular plate portion being abuttable against one end face in axial direction of the cam shaft; and a tapered portion linking the circular plate portion to the ring-shaped portion at a radially intermediate region. The tapered portion is provided with a plurality of punched portions whose radially inner faces are provided with a partial circular arc shape so as to come into area contact with an outer circumferential surface at the one end face in axial direction of the cam shaft.