PURPOSE: To obtain a good casting without any defect by dipping the lower surface of a gas permeable mold held in a chamber into molten metal, reducing the pressure in the chamber, acting the reduced pressure to the mold and introducing the molten metal into a cavity.

CONSTITUTION: The gas permeable mold 2 is held in a chamber 1 and the lower surface of the mold 2 is dipped into the molten metal and by reducing the pressure of the chamber 1, the reduced pressure is acted on the mold 2 and the molten metal is introduced into the cavity 4 in the mold 2 from a sprue 8 in the mold 2. This sprue 8 is opened directly on the lower surface of the mold 2 from the cavity in the mold 2 and also, the diameter of the sprue 8 is set to 70-80% of the max. thickness of the cavity 4 and the sprue length from the cavity 4 to the lower surface of the mold 2 is set 1.6-2 times the sprue diameter. By this method, the good casting without defect can be obtd. in the casting condition of good pouring yield without waste of the molten metal.