PURPOSE: To reduce the number of steps in the manufacture of molding dies by driving plural pieces of anchor bolts to a die body of molding dies, enclosing these with plastics, setting these in molding flasks and substituting the plastics with molten metal.

CONSTITUTION: Plural pieces of anchor bolts 8 are properly drirven to a die body 1 manufactured by casting or forging, and are enclosed by an expanded polystyrene 3. The polystyrene 3 is set on a molding board, and the circumference thereof is enclosed with a die flask 4. Molding sand 5 is put therein and is compacted. The flask 4 is turned over, and a top part flask 6 is placed thereon, and again sand is packed. A runner 9 and a riser 10 are provided. The body 1 is beforehand preheated, and molten metal 11 is charged through the runner 9 to substitute the polystyrene 3 with the molten metal 11. Upon cooling of the charged molten metal, the flasks 4, 5 are removed and the casting plan parts are cut off, whereby the one piece molding die cast with the body 1 in the die base part 2 is obtained.