To enable feeding and distribution of molten metal while airtight condition inside a holding furnace is constantly maintained and to ensure quantitativeness in molten metal distribution from the holding furnace to a metallic mold of a casting machine.

The holding furnace includes: a protuberance part 2 provided in the sealed holding furnace 1; a molten metal storing/holding part 3 that makes the molten metal P storable in the holding furnace 1 across the protuberance part 2; a suction tube 4 that communicates from the lower part of the holding furnace 1 through the protuberance part 2 into the holding furnace 1; a suction valve 5 that opens/closes the upper opening end of the suction tube 4; a molten metal pouring tube 6 that communicates from the inner bottom part of the molten metal storing/holding part 3 into the holding furnace 1; a molten metal pouring valve 7 that opens/closes the upper opening end of the pouring tube 6; a vacuum device 8 for making the inside of the holding furnace 1 in a negative pressure condition; and a pressurizing device 9 that makes the inside of the holding furnace 1 in a pressurized condition. Then, the upper opening end of the suction tube 4 is released by the suction valve 5 and, simultaneously, the vacuum device 8 is made to operate, releasing the upper opening end of the pouring tube 6 by the pouring valve 7 and at the same time enabling the pressurizing device 9 to operate.