A photoreceptor device includes a photoreceptor unit, a detector, an amount-of-light controller, and a correcting unit. The photoreceptor unit includes one or more photoelectric converter elements, and converts received light into an electric signal and outputs the electric signal. The detector detects an illuminance of ambient light received by the photoreceptor unit, on the basis of the electric signal. The amount-of-light controller controls an amount of light incident on the photoreceptor unit. The correcting unit corrects the illuminance of ambient light detected by the detector, on the basis of the electric signal output from the photoreceptor unit when the photoreceptor unit is shielded from light.