PROBLEM TO BE SOLVED: To acquire on a machine tool a position where a work w becomes unbalanced.SOLUTION: Force sensors 5 and 6 for measuring the force working on each of a pair of fixed sensors 1 and 2 arranged straight on the center line of rotation are provided, and the position on the center line of rotation in which the mass that gives rise to an imbalance is calculated on the basis of signals outputted by the force sensors 5 and 6. Further, the phase angle in which the imbalance inviting mass is present is figured out in the position where the force reaches the maximum. By causing a controller 14 of the machine tool to calculate these sets of data, balance measuring and correction processing of the work w is are performed.SELECTED DRAWING: Figure 1
