In a method of manufacturing semiconductor wafers, front and back surfaces of the semiconductor wafers are simultaneously polished with a double-side polishing machine that includes: a carrier for accommodating the semiconductor wafer; and an upper press platen and a lower press platen for sandwiching the carrier. The method includes: accommodating the semiconductor wafer in the carrier while a thickness of the semiconductor wafer is set to be larger than a thickness of the carrier by 0 μm to 5 μm; and polishing the semiconductor wafer while feeding a polishing slurry to between the surfaces of the semiconductor wafer and surfaces of the press platens. In the polishing, an allowance of both surfaces of the semiconductor wafer is set at 5 μm or less in total.