An exposure device includes a reference current generating unit generating a reference current for each image of respective colors, a photoelectric current generating unit generating a photoelectric current in response to a light amount of the light emitting element, a driving unit driving the light emitting element, a first controller, a drive voltage holding unit holding a drive voltage given to the driving unit, a second controller controlling the driving unit based on the drive voltage held, a comparison current generating unit generates a comparison current, a difference current generating unit generating a difference current, of each color, corresponding to a difference between the reference current of each color and the comparison current. The first controller compares a value obtained by adding the difference current of each color to the photoelectric current with the comparison current to control the driving unit so that the photoelectric current becomes the reference current.