PURPOSE: To prevent molding material from slipping down and defectives from occurring by providing several catch-holes on the molding surface of the fixed mold and catching the molding material to the catch holes before the movable mold is set to the fixed one.

CONSTITUTION: Downward stretching catch holes 4 are provided at several places on the molding surfaces 2a of the projecting section 2 of the fixed mold 1. The fixed mold 1 and the movable mold 5 are preheated to 140W160°C. The molding surface 2a is charged with molding material M, and the molding material M is compressed and forced partially into the catch holes 4. Hereby, places charged with molding material M can be fixed by anckoring effect and the fixed mold 1 is prevented from slipping down from the molding surface. When the movable mold 5 is set to the fixed one 1, the molding material M is heated, compressed into a mold, begins gelling and the abutting sections 3, 7 of both fixed and movable mold 1, 5 abut on each other, while the molding material M is compressed into the shape of the molded piece and hardened completely. M shows the molding material of sheet molding compound composed of glass fiber, calcium carbonate, unsaturated polyester resin, etc.