A system can include: a dividing unit which divides a light scanning within a rotation angle range into a right scan light of a first angle portion and a left scan light of a second angle portion; a right-side scan light generation unit which reflects the right scan light toward a right-side region portion of an irradiation region; and a left-side scan light generation unit which reflects the left scan light toward a left-side region portion of the irradiation region. Both end fields of the region are irradiated by the light from the middle part of the rotation angle range. A center field of the region is irradiated by the light from the end parts of the rotation angle range.