PROBLEM TO BE SOLVED: To precisely control a deflection amount of a wafer to a wanted amount as well as reduce the deflection amount of the wafer.SOLUTION: A slicing method of a semiconductor single crystal ingot 13 is improved, in which a cylindrical semiconductor single crystal ingot 13 is bonded and held by a holding jig 14 while it is rotated by a predetermined rotation angle around a crystal axis 13b of the ingot 13 which is different from a central axis 13a of the cylinder of the ingot 13, and in this condition, the ingot 13 is sliced by a cutting device 16. The configuration is featured by determining a predetermined rotational angle when the ingot 13 is bonded and held by the holding jig 14 such that a deflection amount of the wafer having been sliced by the cutting device 16 becomes a predetermined amount.