Method for the production of an expanded fiber-reinforced thermoplastic resin molding

The present invention provides a method for producing an expanded fiber-reinforced thermoplastic resin molding, the method using a mold comprising a female and male dies and comprising processes for supplying a molten thermoplastic resin containing reinforcing fibers whose average fiber length is maintained at 1 mm or more to between the female and male dies to charge a mold cavity with the molten thermoplastic resin, opening a part or the whole of the mold in the thickness direction of a molding after the charging, and cooling a molding while maintaining a cavity clearance at the thickness of a final molding, the method wherein the mold cavity of the mold is interconnectable to the atmosphere, the method further comprising steps for (a) forming a solidified layer in the surface of the molten thermoplastic resin charged in the mold cavity, followed by (b) breaking at least a part of the solidified surface layer, introducing the air through the broken part concurrently with or after the breakage, and opening a part or the whole of the mold concurrently with the introduction of the air so that a cavity clearance defined there reaches the thickness of the final molding.