Optical scanner and image forming device

The optical scanner according to the present invention, by using a single plurality of light beams deflected by the deflector for scanning. The scanner includes a light configured to emit a plurality of beams and a plurality of light sources each include a pre-scanning optical system. A first pre-scanning optical system to emit a first light beam deflected by the deflecting unit. The second pre-scanning optical system emitting a second light beam, and disposed in the first pre-scanning optical system different from the position in the rotation axis direction of the position of the deflector.