PURPOSE: To provide an apparatus for driving a rotary polygon mirror which is characterized by low manufacturing costs and precision high speed rotation.

CONSTITUTION: A rotary polygon mirror 36 and a shaft 38 are formed integrally. An orbital channel 38a is formed on the outside of the shaft 38, and a ball 40b as a rolling body is held between the channel 38a and outside wheel 40a fixed to a housing 22. A rotor 26 fixed to the shaft 38 is rotated by the drive of a stator electromagnet 24. During the rotation of the rotor 26, the ball 40b rolls directory on the orbital channel 38a in a bearing 40.