PURPOSE: To make it possible to chamfer semiconductor wafers and produce a same chamfered shape and protect the shape from being affected by the thickness of the semiconductor wafers.

CONSTITUTION: First, the top surface 12A of a wafer attracting rack 12 is positioned on the same surface as on an horizontally extended border (s) line.between an even surface 16 and an upper curved surface 18A formed on a grinding stone 14. Then, the wafer attracting rack 12 is lowered by dimensions to which half (t/2) a preliminarily measured thickness (t) of a semiconductor wafer 10 and half (X3/2) the thickness X3 of the even area formed in the central part around the peripheral edge of the semiconductor wafer 10 are added. Then, the wafer attracting rack 12 is horizontally moved in the direction in which the rack 12 is approaching the grinding stone 14 so that the upper end 10A of the semiconductor wafer 10 is made to abut on an upper slope surface 20A of the grinding stone 14, thereby abrading the upper end area 10A. When the abrasion of the upper end area 10A is finished, the wafer attracting rack 12 is lowered by dimensions in which the thickness (X3) of the even area of the semiconductor wafer 10 is deducted from the width (w) of the even surface 16 of the grinding stone 14 and the lower end area 10B of the semiconductor 10 is abraded with the lower slope surface 20B.