PURPOSE: To suppress the occurrence of casting defects and obtain good castings by applying a mold coat having air permeability on a lost foam pattern and chiller, respectively, then mounting this chiller 2 at the thick part of the lost foam pattern and embedding this lost foam pattern into casting sand.

CONSTITUTION: The mold coat having the air permeability is applied on the lost foam pattern 1 and the chiller 2, respectively and is dried; thereafter, the chiller 2 is adhered to the thick part 1a of the lost foam pattern 1 by an adhesive. The gases in molten metal and the combustion gases in the lost foam pattern 1 are discharged through the mold coat layer 3 into the molding sand when the lost foam pattern is embedded in the molding sand and the molten metal is poured to substitute the lost foam pattern 1 with the molten metal. The solidifying speed of the molten metal is increased by the chiller 2. The castings free from casting defects, such as shrinkage cavities, burn-on and blowholes, are obtd.