PURPOSE: To enable the manufacturing of a great number of grindstones at low cost, by baking a molded grindstone workpiece to cause an intermediate mold to completely fly away and by using a metal mold for a semipermanent period of time.

CONSTITUTION: An intermediate mold 2, which is made of plastic or the like and conical, is tightly fitted in a metal mold 1 made of ductile cast iron. A grindstone material such as alumina and a binder are put in the intermediate mold 2 and press-molded by an appropriate press means 3. The press-molded workpiece 4 is knocked by a means 5 out of the metal mold 1 as the intermediate mold 2 remains adhesive to the outside surface of the workpiece. The workpiece 4 is then baked in a furnace. At that time, the intermediate mold 2 adhesive to the outside surface of the molded workpiece 4 completely flies away due to the baking heat. According to this method, the metal mold 1 is used for a semipermanent period of time to manufacture a great number of grindstones at low cost.