by the inside surface 204e of the head portion 204a of the holding claw and the wire ring engaging surface 204g is less than 90 degrees thereby preventing the wire ring 202 engaged with the protrusion 204f from being removed from the protrusion 204f in the upward direction as shown in fig2 in addition concave portions 204h are formed on the head portion 204a between the engaging portions 204d so as to prevent a sink at the time of injection molding the holding claw the holding claw 204 is formed by means of the following processes as shown in fig3 the holding claw 204 is injection molded by the outer metal mold 207 which can move outwardly in the radial direction to the left in the drawing and the inner metal mold 209 which can move in the direction of the thickness of the wheel cover main body the outer metal mold 207 molds the outside surface of each holding claw 204 i e the engaging portions 204d the outside surface and side surface 204j having the curved surface 204i of the leg portion 204b the concave portions 204h as well as the slit 204c of each holding claw 204 and engaging surface 204g of the protrusion 204f and so on the inner metal mold 209 molds the inside surface 204e in the radial direction of each holding claw 204 the protrusion 204f and so on the holding claw 204.