To suppress irradiation positions of a plurality of scanning lines from being deviated in a scanning optical apparatus and an image forming apparatus.
The scanning optical apparatus comprises: a rotating polygon mirror which symmetrically deflects and scans luminous fluxes emitted from at least two light sources; scanning lenses which focus the two luminous fluxes scanned with the rotating polygon mirror on respective image carriers; and an optical box 350 which disposes the rotating polygon mirror and the scanning lenses. The scanning optical apparatus is characterized by that the optical box 350 has a plurality of restraining parts for fixing on the image forming apparatus, at least the two restraining parts are symmetrically arranged with respect to the optical axis of the scanning lenses or the rotation axis of the rotating polygon mirror.
Hiroyuki Nakagawa
Kosuke Tobita