Provided is an optical scanning device that can consistently obtain a light beam having a desired beam spot diameter without allowing an aperture to block parallel ray to be admitted, and that can be manufactured at lower cost. The optical scanning device has a light source that emits laser light, a collimator lens that converts the laser light emitted from the light source into parallel ray, and a lens holder that holds the collimator lens and has an aperture portion for fairing the laser light, the aperture portion being formed integrally with the lens holder. The optical scanning device also may have a collimator lens having a lens surface with which an aperture portion for fairing the laser light is brought into close contact.