PURPOSE: To prevent thermal deformation of the molding by heating or cooling the hard vinyl chloride molding fitted into the set base while the side thereof is held with a holder.

CONSTITUTION: The rib plate 1 is set on the set base arranged on the body 17 of the vertical conveyors 6 and held on both sides with the holder 5. Under a such condition, with the driving of the vertical conveyor 6, the rib set on the base 4 moves upward and is heated by the radiation heat of the infrared ray heater 8 in the heating zone whereby the foaming agent in the printing pattern is foamed. After the heating, the rib plate is cooled with the cool air nozzle of the cooling zone 9. Thus, as the molding is fitted into the set base while heated or cooled being press held, the thermal deformation can be minimized.