A wafer (5) substrate is polished by disposing the wafer substrate between an abrasive cloth (2) on a polishing platen (1) and a plate (4), and relatively rotating the polishing platen (1) and the plate (4) for mirror polishing the surface of the wafer (5) substrate with the abrasive cloth (2). A liquid is fed onto the plate (4) side surface of the wafer substrate so that the wafer substrate is directly held to the plate (4) by the adsorption force of the liquid, while performing the mirror polishing.
