PURPOSE: To improve the processing of a terminal part and outside appearance by placing a fusible material onto a back surface and preshaping a skin member which is cut larger than the adhesion range of an attached basic member and turning back the excessive part of the terminal to the back surface side and fusing the terminal part.

CONSTITUTION: When a skin member 5 is to be attached, the skin member 5 is cut B larger than the area of a skin member adhesion range A on a basic member 6. Then, the cut skin member 5 is pre-shaped to a form set along the adhesion range A through the vacuum suction in which air is discharged from an air vent hole 8, by the shaping part 7 of an upper mold 4. At this time, the excessive terminal part (x) of the skin member 5 which bulges out from the shaped part 7 is turned back inside the shaped part 7 by a hook member 11, and nipped between a block 10. Then, a high frequency current is allowed to flow in the block 10 and the hook member 11 from an electric circuit 12, and a fusible material 13 which is placed onto the back surface of the skin member 5 is induction-heated and molten. Then the terminal part (x) of the skin member 5 is pushed into the recessed groove 6a of the basic member 6 by a plug 9 built in the upper mold 4.