PURPOSE: To constitute the title method so that a saddle type wafer is not cut off by correcting a displacement of a blade during its movement by a pressing device, by a method wherein the pressing device and a blade sensor are moved along a cut fringe of an ingot.

CONSTITUTION: After a doughnutlike blade 14 is extended, air is spouted through an air pad 30, the blade 14 is bent downward and sufficient rigidity is given to the vicinity of an inner circumferential edge 16 of the blade 14. Cutting of an ingot 20 is begun on the basis of the bent position. The position of the blade 14 is detected by a sensor 32 and stored. Then a work support rest is moved by a cutting and feeding mechanism and the ingot 20 is cut off. At the time of starting of the cutting, a pair of followers 34 abutting against an outer circumferential surface of the ingot 20 are positioned in a line at a cutting position, the ingot 20 is moved in the direction X by resisting against a spring 40 of the follower 34 according as the cutting position is advanced to the central part and the air pad 30 also is moved according to a change of a cut surface by interlocking with the follower 34. Then a displacement of the blade 14 is detected by the sensor 32 and a distance with a cut fringe is corrected.