A method of manufacturing a thin silicon wafer by slicing a silicon single crystal includes: a thinning step S3 of polishing a rear surface of the silicon wafer to reduce the thickness of the silicon wafer after a device structure is formed on a front surface of the silicon wafer; a mirror surface forming step S4 of processing the rear surface of the silicon wafer into a mirror surface using a chemical mechanical polishing method; and a modifying step S5 of dispersing abrasive grains that are harder than those used to form the mirror surface in the mirror surface forming process and forming a damaged layer, serving as a gettering sink for heavy metal, on the rear surface of the silicon wafer using the chemical mechanical polishing method. The thickness T5b of the damaged layer W5b in a wafer depth direction is set by the chemical mechanical polishing method in the modifying step S5 to control the gettering capability of the damaged layer.