PURPOSE: To easily form a film of a desired metallic compound on the surface of a metallic material by setting the material in a vessel contg. an atmospheric gas such as gaseous N2, gaseous hydocaron or gaseous H2 and by irradiating laser light on the surface of the material from the outside of the vessel to keep the surface at a temp. at which the metallic compound can be formed.

CONSTITUTION: A metallic material to be treated such as a Ti plate 1 is mounted on a cooling table 2 in a treating vessel V, and after evacuating the vessel V from the evacuating valve 8 of a vacuum pump, gaseous N2 is introduced into the vessel V from a gas introducing valve 6. Laser light from a laser generator 4 is then irradiated to the surface of th Ti plate 1 through a reflecting mirror 5 and a laser light irradiating window 3 made of a transparent material such as glass. By keeping the surface of the Ti plate 1 at about 1,400°C, a TiN film having about 5μm thickness is formed on the surface.