The method of the present invention is capable of abrading a work piece with fixed load. The method comprises: a first abrading process, in which pressure of a cylinder chamber of a cylinder unit suspending an upper abrasive plate is adjusted so as to apply first pressure to the work piece via the upper abrasive plate without applying full weight of the upper abrasive plate; and a second abrading process, in which the pressure of the cylinder chamber is readjusted so as to apply second pressure, which is higher than the first pressure, to the work piece via the upper abrasive plate without applying the full weight of the upper abrasive plate.