To prevent deterioration in an image formation state by suppressing an inclination of an optical element in a housing even when a heat deformation occurs in the housing by a temperature rise in image formation and reducing an error at a position of an optical path of an image light.

An optical scanner 1 stores mirrors 22, 26 inside a housing 20 consisted of a thermoplastic material. The mirror 22 is held by a holding part 41 and the mirror 26 is held in a holding part 45 via holding bodies 50. The holding parts 41, 45 are integrally formed in an erection state in an inner side surface 20A. The holding bodies 50 are constituted by fixing the mirror 26 to an opening end part 52 holding a bent part 53 with an attachment part 51. When heat rises in the housing 20, the opening end part 52 is inclined in a direction opposed to an inclination direction of a base end part 45 by the heat deformation of the inner side surface 20A.