PURPOSE: To produce a wafer with high accuracy by controlling the posture of a columnar member material in such a manner that the predetermined cutting face of the columnar member material becomes parallel with a cutting blade.

CONSTITUTION: The displacement amount of an inner circumferential blade 22 is inputted from a non-contact type displacement gauge 32 into a control section 30 which calculates an angle given by the crystal face (predetermined cutting face) of an ingot 20 and the inner circumferential blade 22 on the basis of a detected value obtained from the displacement gauge 32. The control sec tion 30 outputs a drive signal for respectively driving piezo-electric elements 28A to 28D on the basis of the calculated value so that the inner circumferential blade 22 becomes parallel with the predetermined cutting face of the ingot 20, and controls the posture of the ingot 20 by the extension and retraction of each of the piezo-electric elements 28A to 28D. During the cutting operation, the displacement amount of the inner circumferential blade 22 is successively detected at every predetermined period of time and, on the basis of this defected value, the posture of the ingot 20 is continuously controlled.