To inhibit the projection onto the rear window glass and to improve the design by coarsening at least of a part of a surface opposite to the rear window glass.

An upper member 10 is formed out of ABS by molding, and provided with the design having the same color as a body of an automobile 2 and high gloss by coating. A lower member 11 is formed out of AES by molding, and is black by using a black material resin in the molding. Further the whole surface of a lower surface 12 opposite to the rear window glass of the lower member 11 is provided with fine wrinkled pattern transferred from a mold surface in the molding, so that the gloss is lowered by the coarsening. The reflection of light on the lower surface 12 is reduced, and the projection of a reflected image to the rear window glass 20 can be reduced, whereby the impairing of the design of a rear spoiler 1 and that of the automobile 2 can be prevented.