PURPOSE: To produce various products and to improve the yield by filling up expendable model into the mold after producing the expendable model by material for complex and foaming organic agent and next pouring molten metal into the mold, to substitute the organic agent to the molten metal.

CONSTITUTION: The mixture of the material 2 for complex and foaming organic agent 1 is blown in the metallic mold 3 to form by foaming, and the expendable model is produced. The expendable model is filled up in the mold 8 and also at the time of pouring the molten metal 5, the foamed organic agent is substituted to the molten metal 5, and the complex casting with the material 2 for complex and the metal is obtd. As the material 2 for complex is easily positioned at necessary position in the metallic base metal, the various products are produced, and also the yield is improved.