PURPOSE: To conduct surely the assembly of parts and the installation of them to a product main body by a method in which in an insert member comprising a plate in which an anchor is formed to prevent the movement of installed members when other members are installed to installation parts, the anchor penetrates a surface layer and fixed to the surface layer in a state in which the anchor is installed to be buried in a core.

CONSTITUTION: An insert member 14 is equipped with nuts 16 and anchor pins 17. The nuts 16, the foamed material core 2 side of which is closed like a bag, are used to prevent the leakage of a liquid resin during molding. A surface layer 4 made of ERP and unevenness (for example, grating type channels) for bonding the nuts 16 firmly with the core 2 are formed on the core 2 side surface of the nut 16. Since the insert member 14 is bonded firmly to the surface layer 4 and the core 2 by the anchor pins 17 and equpped with the nuts 16, the postprocessing of the insert member 14 after molding is completely unnecessary.