PURPOSE: To obtain molded goods having excellent quality and shapes of a wide range without receiving restrictions on the shapes by using a pressure resistant collapsible core and specifying a method of removing this core.

CONSTITUTION: The pressure resistant collapsible core 1 is formed by using the collapsible material, such as paper and grains, and is disposed between a cope 2 and a drag 3 to form a mold 4. A molding material, such as molten aluminum, synthetic resin or ceramic material is poured according to the material quality of molded goods into a cavity part 5, by which the molded goods meeting the shape of this cavity part are formed. The removal of the pressure resistant collapsible core 1 is executed by removing the removable parts and removing the remaining heat of the parts where the remaining heat is removable. The remaining parts are almost completely removed and dissipated by dissolution using a solvent, such as water, or combustion by heating, etc.