An object of the present invention is to provide a method of polishing silicon wafers, capable of suppressing generation of undesired sounds from carriers and reducing the thickness variation of the wafers after polished.The method is a wafer polishing method in which wafers 20 are polished by supplying a polishing solution to surfaces 30a of a pair of polishing pads 30 positioned above and below carriers 10 each having a circular hole 11 for retaining the wafers 20, the carriers 10 being thinner than the wafers 20; and sliding the polishing pads 30 relatively to the carriers 10, thereby simultaneously polishing both surfaces of the wafers 20 retained in the carriers 10. The method is characterized in that information sourced from the carriers 10 when a difference between the thickness of the carriers 10 and the thickness of the wafers 20 reaches a predetermined value is detected to calculate the thickness of the wafers 20, thereby terminating polishing.