A machine tool re-machines a workpiece after positioning drive motors, a hob and the workpiece by stopping the drive motors with the rotational positions of the drive motors, the hob and the workpiece corresponding to their respective zero positions. For this purpose, a drive control section recognizes, based on the rotational-speed ratio of the drive motor corresponding to the hob and the hob and/or the rotational-speed ratio of the drive motor corresponding to the workpiece to the workpiece, and detection signals from detection sensors detecting that the rotational positions of the drive motors are at their respective zero positions, detections signals when the rotational positions of the drive motors and the rotational positions of the hob and the workpiece correspond to their respective zero positions, and stops the drive motors with the rotational positions of the drive motors, the hob and the workpiece corresponding to their respective zero positions.