A light scanning device is provided. The light scanning device includes: an oscillating mirror which oscillates rotationally and reflects a light beam to be scanned over a scanning range, the scanning range including a first scanning range and a second scanning range set across a center of the scanning range; a detection unit including a light receiving face, on which the light beam is incident, to detect the light beam; and first and second stationary mirrors which reflect the light beam reflected by the oscillating mirror to the first scanning range and the second scanning range, respectively, to be incident on the light receiving face, wherein an incident pattern of the light beam reflected by the first stationary mirror incident on the light receiving face is different from an incident pattern of the light beam reflected by the second stationary mirror incident on the light receiving face.