PURPOSE: To control a cooling speed of a die extending over a long period of time without causing a corrosion by providing a cavity on a part which becomes the back of the die engraving surface of the die, containing a hollow cooling block therein and allowing the cooling block to abut or separate on or from the inside surface of the die, while feeding cooling water to the block at the time of casting.

CONSTITUTION: At the time of casting, a core 8 is held in the upper die 1 in a die open state, slide cores 5, 5 are moved, and also, the upper die 1 is allowed to descend and set to a die closed state. In this case, a cooling block 13 is in a descend position, and its upper face 13a and side face 13b are in a state that they are separated from the inside surface of the lower die liner 4. Subsequently, a molten metal is injected to a cavity 6 through a runner 7, and as soon as filling to the cavity 6 is completed, pressurization is executed. Next, the cooling block 13 is allowed to ascend by a cylinder 14, and its upper face 13a and side face 13b are allowed to abut on the inside surface of the lower die liner 4. To the inside of the cooling block 13, cooling water is supplied from a cooling water supply device 15, and the lower die liner is quenced, and by following it up, a cast part is also quenched. Accordingly, the die is opened in a short time and the cast part can be taken out of the die.