Abstract: A metal substrate is embedded in a diffusion and penetration processing agent containing metal oxide, active metal and catalytic compound and heat treatment is carried out, so that an oxidation resistant alloy coating film containing the metal constituting the metal oxide and the active metal is produced. Al203, Cr2O3, SiO2 or the like are used as the metal oxide, Hf, Zr, Y, Ti, La, Ce, Mg, Ca or the like are used as the active metal, and NH-14Cl, NH4F, HCl, NaCl, NaF or the like are used as the catalytic compound. The metal substrate is Ni, Ni-based alloy, Fe-based alloy, and Co-based alloy. Heat treatment is carried out, for example, at a temperature of 700˜1340° C. for 1 minute˜25 hours in an atmosphere of inert gas or hydrogen gas.