PURPOSE: To form the title coating film having high adhesive strength to a substrate by forming a conductive coating film on the surface of an insulating substrate, and forming a mixing layer at the interface between the substrate and film by ion implantation.

CONSTITUTION: The surface of the insulating substrate (diamond,sapphire, etc.) is specularly finished, and a metallic material (Hf, Ti, etc.) having excellent wear resistance is deposited in about 500 on the surface by sputtering to form a conductive coating film 2. The ions of Ar+ in the amt. of about 1×1016 unit/cm2 are then implanted by the accelerating voltage at about 350KeV from the surface of the film 2 by ion implantation. As a result, a mixing layer 3 is formed at the interface between the substrate 1 and the film 2 by the mixing effect, and the adhesive strength between the substrate 1 and the film 1 is remarkably improved. By this method, the conductive coating film 2 capable of being utilized for the reproducing stylus of an electrostatic capacity-type video disk, etc., is obtained on the insulating substrate 1.