PURPOSE: To execute an effective pressurized casting by delaying the cooling of a filled molten metal and to facilitate the knock-out of a casting from a mold as well by fitting the sleeve quipped with the sprue of a heat insulating material having a specified draft on the closing plate of the upper face of the mold in the cast of casting with a full mold process.

CONSTITUTION: A polystyrene made lost-wax pattern 7 is set inside a flask member 2 and a molding sand 9 is filled up with sufficient density to make a full mold process mold. A sleeve 6 is fitted to the closing plate 5 provided on the flask member 2 and the heat insulating material made sprue 10 having 5/100 draft is set up at the inner side thereof as well. After reducing the pressure of the mold inside by exhausting from the pressure reducing port 2b of the flask member 2 a molten metal is poured from the sprue 10 and the lost-wax pattern 7 is dispensed by burning and the molten metal is cast. Immediately thereafter a pressurizing device 3 is fitted to the sleeve 6 and the molten metal is pressurized by a gaseous body to make a casting. Since the heat insulating member 10 can easily be removed form the sleeve 6 without the breakdown of the gaseous body pressurizing device 3 by being overheated through the sleeve 6 by the heat insulating material made sprue 10 the knock-out of a casting can also be done simply.