separately providing a mechanical processing section for processing a surface of a substrate by a mechanical action, and an electrolytic processing section, having a processing electrode with an ion exchanger, for processing the substrate by applying a voltage between the processing electrode and the substrate while keeping the ion exchanger in contact with the substrate;

processing the surface of the substrate with the mechanical and electrolytic processing sections by moving the substrate and the mechanical processing section relative to each other and moving the substrate and the processing electrode relative to each other while keeping the ion exchanger and the mechanical processing section in contact with the substrate such that the electrolytic processing section electrolytically processes the surface and the mechanical processing section removes a passive film formed during processing with the electrolytic processing section; and

re-processing the surface with the electrolytic processing section after said processing of the surface with the mechanical and electrolytic processing sections.