An optical scanning device includes a light source having plural light emitting portions, a deflection unit that deflects and scans plural light beams emitted from the light source in a main scanning direction, and plural optical element groups disposed between the light source and the deflection unit and including an optical element having a negative refractive power along a sub-scanning direction intersecting the main scanning direction. An interval in the sub-scanning direction of the plural light beams is adjusted by tilting the optical element having the negative refractive power on an axis along the main scanning direction.

An optical scanning device includes a light source having plural light emitting portions, a deflection unit that deflects and scans plural light beams emitted from the light source in a main scanning direction, and plural optical element groups disposed between the light source and the deflection unit and including an optical element having a negative refractive power along a sub-scanning direction intersecting the main scanning direction. An interval in the sub-scanning direction of the plural light beams is adjusted by tilting the optical element having the negative refractive power on an axis along the main scanning direction.