PURPOSE: To easily and surely increase the thickness of a film and to improve the heat, oxidation and corrosion resistances by sticking a mixture of powders of the constituent metallic elements of an intermetallic compd. for coating to the surface of a body to be treated and heating this body.

CONSTITUTION: In the case where an intermetallic compd. for coating is Ti3Al, Ti and Al powders are mixed in a prescribed ratio and this powdery mixture is spread and stuck to the surface of a body to be treated. This body is then heated to a temp. at which the intermetallic compd. is formed or above to coat the surface of the body with the compd. It is not necessary to make the ratio between the powders strictly equal to that between the constituent metallic elements of the intermetallic compd.