PURPOSE: To improve durability of a mold for resin molding, by a method wherein the inside of a void of a porous flame spray metallic film which is used as an engraving part is filled with a resin material.

CONSTITUTION: A mold 1 is formed of a base metal 2 made of cast iron which is used as an engraving material, flame spray metallic film 3 made of a zinc- based alloy and applied to an opening part 2a of the said base metal 2 and a reinforced body 4 supporting the said flame spray metallic film 3 from behind. As the flame spray metallic film 3, impregnated with resin, a resin material 3b is entered into a space among a large number of flat flame spray metallic films 3a generated on crushing of a liquid droplet of a molten metal. As the inside of a void of a porous flame spray metallic film is filled with the resin material, the said flame spray metallic film is strengthened drastically, it is hard to generate a deformation on the same even if injection molding pressure of more than 100kg/cm2 is applied to the same and durability of the mold is improved drastically.