PURPOSE: To obtain a molded article free from gas bubbles and having a sandwich construction wherein the surface consists of an FRP layer and the internal part consists of a foamed body layer filled with a resin, by a method wherein a foamed body is impregnated with a resin, the surface of the body is covered by a glass base material, and pressure molding is conducted at a low pressure.

CONSTITUTION: The foamed body 1 is introduced into a liquid resin 2. In the liquid resin 2, air in the foamed body 1 is expelled by compressing the body 1 by rolls 3, and thereafter, the body 1 is sufficiently impregnated with the resin 1 when recovering its original shape. Next, the surface of the body 1 is covered by a glass mat, followed by molding at normal pressure by applying a low pressure. Accordingly, a reinforced plastic can be obtained which has a bubble-free sandwich construction wherein the surface consists of the FRP layer and the internal part consists of a foamed polyurethane layer filled with the resin.