PURPOSE: To insulate the heat of molten metal from the inside and to make a supply pipe compact and reduce energy loss by coating the outside circumference of the supply pipe for pressure feeding of the molten metal to a casting machine with refractories and providing a heat source in the inside.

CONSTITUTION: The outside circumference of a pipe 11 for pressure feeding of molten metal 13 is coated with refractories 10. At this time, ferrous metals are used for the refractories 10 when the molten metal 13 is zinc or magnesium and nonferrous metals of ceramic type are used when the molten metal 13 is Al. Thence, a heat source 12 such as ceramic heater or sheathed heater is inserted into the pipe 11 in the state in which it is protected with a protection pipe 14. The molten metal 13 is insulated of heat by the heat source 12 mounted in the inside hole of the pipe 11 during pressure feeding of the molten metal, whereby the molten metal is fed by pressure to a casting machine without solidifying.