An optical scanning device is configured to cause a light beam to scan a photosensitive drum to form a latent image on the photosensitive drum. The optical scanning device includes light emitting units configured to emit light beams and a light deflecting unit having deflecting surfaces and being configured to cause the light beams emitted from the light emitting units to reflect at the deflecting surfaces and deflect and scan in a main scanning direction. Also, the device includes a lens disposed between the light emitting units and the light deflecting unit, the lens being configured to cause the light beams emitted from the light emitting units to be directed along the main scanning direction to the deflecting surfaces, and an aperture member disposed between the lens and the light deflecting unit, and having apertures formed in line in a sub scanning direction perpendicular to the main scanning direction.