PURPOSE: To obtain a front surface minor enhanced in accuracy while reducing the remaining of air and strain by holding a plate to be processed between a mold and a lid to heat the same and evacuating the space between the plate to be processed and the mold to supply a fluid into the space between the lid and the plate to be processed under pressure and gradually cooling the plate to be processed thereafter to coat the same with a mirror surface forming material.

CONSTITUTION: A mold 12 having a molding surface 13, the lid 9 of a cavity 10, the fluid compressor supplying a compressed fluid into the cavity 10 and the vacuum pump 2 discharging the air in the space 101 between a resin plate 11 and the molding surface 13 are provided. After the mold is heated by a heating device 3 and the cavity 10 is evacuated by the vacuum pump 2, pressurization is started by the fluid compressor 1 before the resin plate reaches its deformation temp. As a result, the close contact of the resin plate 11 with the mold 12 from the end part of the mold to the center part and vent hole 18 of the mold is performed and the remaining of air between the resin plate and the mold is eliminated to press the rear surface 15 of the resin plate 11 to the molding surface 13 to enable the molding of the resin plate. The resin plate is cooled to curing temp. while pressurization and evacuation are performed or after evacuation is stopped. Then, a mirror surface is formed on the resin plate by the vapor deposition of aluminum.