Injection molding method and injection molding device for transparent resin molded article

An injection molding method for injection-molding a transparent resin molded article having a concave shape, comprising:

• a primary injection step of injection-molding an outer portion from an intermediate portion in a sheet-thickness direction to an outer surface of the transparent resin molded article between a first outer mold and a first inner mold;
• a primary curing step of removing the first inner mold with the first outer mold left behind after the injection molding of the outer portion, thereby inducing sink marks in the inner peripheral surface of the outer portion;
• a secondary injection step of injection-molding an inner portion from the intermediate portion in the sheet-thickness direction to an inner surface of the transparent resin molded article between a second outer mold and a second inner mold;
• a secondary curing step of removing the second outer mold with the second inner mold left behind after the injection molding of the inner portion, thereby inducing sink marks in the outer peripheral surface of the inner portion;
• and
• a tertiary injection step of injecting a resin material into an injection space which is formed between the outer portion and the inner portion by die-matching the first outer mold after the primary curing step and the second inner mold after the secondary curing step.