To prevent the deterioration of working precision caused by the propagation of vibration on the roughing side to the finishing side on a machine tool provided with a plurality of working stations simultaneously roughing and finishing.

This vibration damping device of the machine tool is provided with a vibration detector 21 fixed on a member on the roughing side and a vibrator 25 fixed on a work holding member or a cutter holding member on the finishing side and controls a driving electric current value of the vibrator 25 in accordance with an output signal of the vibration detector 21. It is possible to compensate a positional signal given to a servo control device in accordance with an output of the vibration detector instead of providing the vibrator on the machine tool provided with the servo control device to control a feed motor to change a relative positional relation of a work and a cutter.