PURPOSE:To eliminate the need for a means which combines and adjust the rotray part of a motor and a specular surface by forming a mirror and a rotor for rotational drive in one body, and working the specular surface mirror and the rotor simultaneously. CONSTITUTION:Bearings 2 and 2' are mounted on upper and lower cases 1 and 1' and a shaft 3 is supported thereupon rotatably. The rotor part alpha is arranged in the cavity 6 formed of the upper case 1 and lower case 1', and a polygon mirror 5 is fixed 4 by arc welding or adhesion, etc., to the outer circumference of the end part of a rotary support 7 engaged fixedly with the rotating shaft 3. A magnet 9 is attached in contact with an iron ring 8 where magnetic flux is passed, an iron core 10 is fitted and supported on a drooping support part 11 drooping from the upper case 1, and winding 12 connected to an external power source is provided around the iron core 10. The rotor part alpha is supported on the upper and lower bearings 2 and 2' rotatably around the rotating shaft 3 of the polygon mirror 5, so the angle of deflection of the polygon mirror is decreased.