A servo control apparatus includes a velocity command creation unit; a velocity detection unit; a velocity control gain; a torque command creation unit; a filter configured to attenuate a particular frequency band component in a torque command value; a sine-wave sweep input unit configured to perform a sine-wave sweep in a predetermined frequency range; a frequency characteristics calculation unit configured to calculate a frequency characteristic of a sine-wave; and a filter adjustment unit configured to attenuate a particular frequency band component in a torque command value. A signal is input to the velocity control gain. The signal is obtained by adding a sine-wave to a difference between a velocity command value and a velocity detected. The filter adjustment unit measures an influence of the velocity control gain on a resonance frequency and resonance peak amplitude, while changing a value of the velocity control gain, thereby adjusting the filter.

A servo control apparatus includes a velocity command creation unit; a velocity detection unit; a velocity control gain; a torque command creation unit; a filter configured to attenuate a particular frequency band component in a torque command value; a sine-wave sweep input unit configured to perform a sine-wave sweep in a predetermined frequency range; a frequency characteristics calculation unit configured to calculate a frequency characteristic of a sine-wave; and a filter adjustment unit configured to attenuate a particular frequency band component in a torque command value. A signal is input to the velocity control gain. The signal is obtained by adding a sine-wave to a difference between a velocity command value and a velocity detected. The filter adjustment unit measures an influence of the velocity control gain on a resonance frequency and resonance peak amplitude, while changing a value of the velocity control gain, thereby adjusting the filter.

A motor control device is a motor control device which controls a spindle motor of a machine tool, the device including: a low-pass filter which averages torque command values or drive current values of the spindle motor and calculates averaged load information of the spindle motor; and a time constant calculation unit which calculates, as a time constant of the low-pass filter, a first time constant based on a cut-off frequency according to the rotation number of the spindle driven by the spindle motor, or a second time constant based on a cut-off frequency according to a value produced by multiplying a of cutting tooth number of a tool by the rotation number of the spindle.