PURPOSE: To improve the pouring performance and the feeder head effect by arranging an electromagnetic booster to a mold at the molten metal pouring side and impressing the electromagnetic force to the molten metal.

CONSTITUTION: A superconducting magnet or an ordinary type electric magnet is started and risen to a prescribed magnetic flux density. The mold and the electromagnetic booster are separated and a neck part is covered with a reduced pressure cap. The pressure reduction is started with a vacuum pump and the molten metal surface position is pulled up to a prescribed height. While gradually releasing the pressure reduction, current is simultaneously impressed to the neck part to increase an electromagnetic Lorentz's force and the reduced pressure cap is taken off and the mold is set to the prescribed position. The pouring of molten metal is started by rising the Lorentz's force, and after completing the pouring, the Lorentz's force is risen to a prescribed feeder head pressurized force in a prescribed timing and continued till completing the solidification. The molten metal surface is returned back to a prescribed position of the surface of the feeder head and a cast product is taken out from the mold.