To provide a motor wherein uneven rotational characteristic is stabilized by forming in a high-rotation precision control system a high-gain control system which suppresses oscillations in the control system through a simple method, without the use of expansive and complicated control techniques or energizing method and with high in the response frequency of a servo system.

This motor is formed as brushless motor by fixing a rotor yoke 7 with magnets 7 installed thereon on a motor shaft 5 via a bush 8, faced opposite a coreless stator coil 1 to the magnets 4 with a gap in-between, and installing an encoder 10 for speed control. An adhesive sheet 12 having buffering capability is inserted between the rotor yoke 7 and the magnets 4, and a self- lubricating sheet 13 having a low coefficient of friction and buffering capability is inserted into between the rotor yoke 7 and the bush 8.