PURPOSE: To produce a structure of a composite material inexpensively and with high accuracy, by a method wherein, when a material to be molded consisting of a fiber-reinforced resin and a core are sealed in a metallic mold having a desired shape and the material is molded under heating while pressurizing the interior of the core, the core is produced by inserting a core made of a foamed material into a pressure bag consisting of an adhesive film.

CONSTITUTION: In a method for producing a structure of a composite material wherein the material 58 to be molded consisting of a fiber-reinforced resin and the core 42 is sealed in the metallic mold 60 having the desired shape and the material 58 is molded under heating while pressurizing the interior of the core 42, the core 42 is produced by a method wherein a core 42 made from a thermoplastic foarmed material and being slightly smaller than a desired size is inserted into the pressure bag 40 prepared by jointing an adhesive film. The material 58 is molded under heating while exerting a pressure on the bag 40 of the core 42 so that the bag 40 is adhered to the material 58, and after molding is completed, the residue of the thermoplastic foamed material shrunk in the interior of the bag 40 is removed.