PURPOSE: To form fine ruggedness on the surface of a substrate and to improve the adhesive strength of a film by forming an etching resist layer having fine pinholes reaching the surface of the substrate to be etched on the surface of the substrate and thereafter subjecting the exposed part in the substrate by the pinholes to etching.

CONSTITUTION: The surface of a substrate to be etched is coated with an etching resist having fine pinhles reaching the surface to be etched in the substrate. Then, the surface of the substrate exposed by the pinholes is selectively subjected to etching to form recessed parts on the surface of the substrate. Thus, the surface of the substrate in which a film is to be formed can suitably be roughened, and an excellent film can be formed on the face to be adhered with tight adhesion.