PURPOSE: To obtain a metallic mold of a low cost by subjecting two sheets of superposed blank materials to wire cutting to form cores having the cut surfaces of the same locus combining the cut surfaces so as to provide cavities between the two cores and mounting the same to mold blocks.

CONSTITUTION: Two sheets of the blank materials 1, 2 having the same thickness are superposed and are subjected to wire-cut electric discharge machining to form 4 pieces of the cores 1a, 1b, 2a, 2b having the cut surfaces of the same locus. The cores 1a, 2a are then combined in such a manner that the cut surfaces 8, 9 faces each other. The cores are mounted to the mold blocks 12, 14 by pressing one side faces of waveform parts 4 to one side face of waveform parts 5. The surfaces 8, 9 are simply subjected to finish polishing and are otherwise hardly worked. The desired metallic mold is thus manufactured in a short period at a lower cost.