PURPOSE: To prepare molding reduced in the difference of thermal expansion with a metal plate and easy in the mounting to a car body by arranging an intermediate member wherein a positioning jig is fixed to the rear side surface of a core metal plate at a predetermined position in a mold before injecting a design material.

CONSTITUTION: A core metal plate 3 made of a stainless copper plate is prepared and screw holes 35, 35 are provided to the core metal plate 3 at a position where bolts 2 are positioning jigs must be fixed and the bolts 2 are threaded with the screw holes 35 while the screw parts 20 thereof are allowed to protrude to the rear side surface 33 of the core metal plate 3 and the heads 21 of the bolts 2 are allowed to protrude above the front side surface 32 of the core metal plate 3 to obtain an intermediate member 30. This intermediate member 30 is arranged to the inner peripheral surface of an injection mold 4 consisting of an upper mold 41 and a lower mold 42 and a design material is injected to the inner peripheral surface of a cavity and cooled to take out molding. The molding has the core metal plate 3 made of stainless copper and has the design material 10 on the front side surface and also has the bolts 2 at predetermined positions.