An overshoot amount detection method includes a synchronization step of synchronizing a signal of an inertial sensor with a signal of an encoder based on a first synchronizing signal output from the inertial sensor during a signal synchronizing operation and a second synchronizing signal output from the encoder during the signal synchronizing operation, a signal generation step of generating a first signal by twice integration of a first detection signal output from the inertial sensor during a working operation and removal of a low-frequency component contained in the first detection signal and generating a second signal for supplement of the low-frequency component of the first signal from a second detection signal output from the encoder during the working operation, and an overshoot amount detection step of detecting an overshoot amount of an arm based on the first signal and the second signal.

A machine tool is equipped with a rotary table, and a clamp mechanism which clamps the rotary table in a manner so that the rotary table does not rotate. A clamping operation by the clamp mechanism is started after a standby time has elapsed from completion of indexing of the rotary table. The machine tool further includes a positional deviation calculating unit adapted to calculate a positional deviation of the rotary table when the clamping operation by the clamp mechanism is completed, and a standby time changing unit adapted to shorten the standby time in the case that an absolute value of the positional deviation is less than a threshold value, and to lengthen the standby time in the case that the absolute value of the positional deviation is greater than the threshold value.

A machine tool is equipped with a rotary table, and a clamp mechanism which clamps the rotary table in a manner so that the rotary table does not rotate. A clamping operation by the clamp mechanism is started after a standby time has elapsed from completion of indexing of the rotary table. The machine tool further includes a positional deviation calculating unit adapted to calculate a positional deviation of the rotary table when the clamping operation by the clamp mechanism is completed, and a standby time changing unit adapted to shorten the standby time in the case that an absolute value of the positional deviation is less than a threshold value, and to lengthen the standby time in the case that the absolute value of the positional deviation is greater than the threshold value.