PURPOSE: To easily make a mold without division into the upper and the lower molds as one body by filling up molding material around a model formed by ice and removing water by heating the model.

CONSTITUTION: The model having the prescribed shape is formed by using the ice. This model is carried to a molding shop and filled up and stamped in a flask by the molding material, such as molding sand, etc. This molding flask is heated to melt the ice for the model and molten water is dipped out to the outside and also hot air is blown into the mold, the vaporize the water and dry, caused to form a cavity. In this way, the mold for cavity having large and complicated shape is efficiently made.