PURPOSE: To suitably secure the temp. of a metallic mold and to obtain the high quality of a casting by detecting the metallic mold temp. and supplying cooling mediums having different large and small thermal capacities according to the necessary cooling rate into a cooling course in the metallic mold by single or combination.

CONSTITUTION: The metallic mold 1 temp. is detected with a temp. sensor 2 arranged so as to approach a cavity in the matallic mold 8. At the time of needing the high cooling rate by raise of the matallic mold 1 temp. at the initial stage of filling the molten metal, the cooling medium 6A having large thermal capacity is supplied into the cooling course 3 in the matallic mold 1. Thereafter, at the time of needing the low cooling rate by drop of the metallic mold 1 temp., the cooling medium 6B having small thermal capacity is supplied into the cooling course 3 in the metallic mold 1 by simple or combustion. Then, the cooling medium for obtaining the high cooling rate is water and the cooling medium for obtaining the small cooling speed is air.