PURPOSE: To impart a heat insulating effect to the casting mold and to produce a deflectless casting by pouring a molten metal into the casting mold which is coated with a facing material consisting of a far IR radioactive material as aggregate or the casting mold inserted with a plate molding in a facing sand.

CONSTITUTION: The far IR radioactive material is a metal oxide, nitride, carbide and the combined materials thereof and has preferably the prescribed emissivity of a prescribed wavelength. The simple material thereof or the combined materials are calcined at and for a prescribed temp. and time. Both of a graphite facing material and white color facing material are usable as the facing material used as the aggregate of a mold coat. KIBUSHI clay is added and mixed as a binder so and with the far IR radioactive material, then kneading the power under addition of water, press-molding the mixture to a prescribed form and calcining the molding at and for the prescribed temp. and time in the case of using this powder by inserting the powder as the plate molding into the facing sand. The heat insulating effect is imparted to the casting which is a thin casting and attains a rapidly cooled structure, by which the defectless casting is produced.