A multi-beam scanning device for focusing deflected light beams onto an object to be scanned includes a light source unit, a deflector, a pitch adjustment device, and a conical-shape compression-torsion coil spring. The light source unit is rotatable about an optical axis and includes a plurality of light sources to emit the light beams and a plurality of coupling lenses disposed corresponding to the light sources. The deflector deflects the light beams emitted from the plurality of the light sources and passed through the plurality of the coupling lenses. The pitch adjustment device moves the light source unit in a first direction around the optical axis to adjust a beam pitch. The conical-shape compression-torsion coil spring urges the light source unit in a second direction opposite the first direction around the optical axis as well as in the optical axis direction. An image forming apparatus includes the multi-beam scanning device.