PURPOSE: To cast satisfactorily a material forming a solidified shell without any casting defect by positioning the top end of a vent pipe in the central part of a riser part and conducting outdoor air to the central part of the riser part.

CONSTITUTION: Outdoor air is conducted through a vent pipe 3 to the central part in a riser part 4, i.e., in the final solidifying position even if a solidified shell 8 is formed to enclose the entire part of a molten metal 2 in the initial stage of solidification after charging of the metal 2. The metal 2 is therefore kept pressed at all times until it solidifies finally and since the foaming therein is suppressed and the amount with die shrinkage by solidification is made up forcibly, a satisfactory casting having no casting defect is produced.