PURPOSE: To adhere the skin superposed to the surface of a molded product to the side of the molded product without using a vacuum molding jig, by forming a hermetically closed space in the molded product with a hollow structure and connecting the hollow interior to a vacuum suction apparatus to evacuate the same.

CONSTITUTION: A molded product 10, of which the surface must be coated with a skin, is brought to a hollow structure to form a suction chamber 12 and a proper number of communication holes 16 are provided to the molded product by a drill and an adhesive 22 is applied to the front and back surfaces of the molded product 10. The leading end part 28 of the suction pipe 26 connected to a vacuum pump 24 is inserted into the suction chamber 12 from a piercing hole 14 and sealed by a rubber cock 30. Skins 32 heated by a heater 32 are superposed to the front surface 18 and back surface 20 of the molded product 10 and the suction chamber 12 is evacuated. The skins 32 are molded along the front surface 18 and back surface 20 of the molded product 10 and fixed thereto.