PURPOSE: To improve quality of a casting product by arranging spiral introducing projections oil inner circumferential face of a molten metal supplying tube and also arranging a rotating magnetic field generator circulating the molten metal at outer circumference of the supplying tube.

CONSTITUTION: The spiral introducing projections 16 are arranged on the inner circumferential face of the molten metal supplying tube 14 almost over the whole length and also the rotating magnetic field generator C for acting the rotating magnetic field in the molten metal 2 is arranged at the outer circumference of the supplying tube 14. At the time of acting the rotating magnetic field in the molten metal 2 in the supplying tube 14 by working the rotating magnetic field generator C, the molten metal 2 is ascended along the introducing projections 16. Then, the molten metal 2 is poured into the mold B through a sprue 12 by ascending while spirally circulating. After pouring, at the time of stopping the magnetic field generator C, the molten metal 2 at the lower part of the sprue 12 is natually dropped and returned back to a crucible A. At the time of adusting the pouring quantity by adjusting the rotating magnetic field of the magnetic field generator C, solidifying state of the molten metal 2 is improved, and the product quality is improved.