PURPOSE: To provide an auxiliary device for motor of a disk player capable of reducing power consumption and shortening motor starting time in the case of starting the rotation of the disk or in the case of the stop by storing the rotational energy of a rotation shaft when the motor is stopped and giving this energy to the motor at the starting.

CONSTITUTION: When a stop button 20 is pushed, the motor 100 is stopped and also a gear train of gears 10-12 is formed, and the rotational energy of the disk 110 due to inertia is stored in a spiral spring 30. When a start button 21 is pushed, the motor 100 is started and also a gear train of gears 0-13 is formed. At the same time, the spiral spring 30 is restored, and the energy of the spiral spring 30 is transmitted to the rotation shaft 101 at the starting.