PURPOSE: To obtain enough bonding effect without employing backing material and at the same time enhance the degree of freedom of shape of a molded item by a method wherein raising treatment is applied to a surfacing material before blow molding so as to let naps act as legs, by which the surfacing material bites in a base material after blow molding.

CONSTITUTION: A base material 1 is made of olefin-based resin material. A surfacing material 2 consists of a solid layer 3 made of polyvinyl chloride material and a polyvinyl chloride foamed layer 4 laminated to the solid layer. Before the pasting of the surfacing material 2 to the base material 1, buffing treatment is applied on the bond area of the foamed layer 4 so as to produce a large number of naps 7W7 by rubbing a rotating roller, round which cloth, hide or the like is wound, against the foamed layer 4 side. Next, the surfacing material is fixed so that its bond area faces to the inside of a mold and, after that, a parison is extruded in the mold for blow molding. The naps 7 of the foamed layer 4 bite in the resin on the base material 1 side and act as 'legs for connection', resulting in enlarging the contact area between the base material and the foamed layer and preventing the surfacing material 2 from separating.