An optical scanning device is disclosed that includes a light source unit, a light source drive unit, a deflection unit, a scanning image optical system, and a light beam detection unit. In the optical scanning device, the light source drive unit controls an amount of light emission of the light source unit, and a light emission amount control period in which the light source unit is forcibly turned OFF is set to the light source drive unit during a period from when the deflection unit deflects to an edge of a scanning angle for scanning the main scanning area to when the deflection unit deflects to a maximum deflection angle of the deflection unit within a non-image forming period.