A substrate processing method is used to polish a substrate. The substrate processing method includes rotating a substrate 13 by a motor 12, polishing a first surface of a peripheral portion of the substrate 13 by pressing a polishing surface of a polishing mechanism 20 against the first surface, determining a polishing end point of the first surface by monitoring a polished state of the first surface, stopping the polishing according to the determining the polishing end point, determining a polishing time spent for the polishing, determining a polishing time for a second surface of the peripheral portion based on the polishing time of the first surface, and polishing the second surface for the determined polishing time.