An optical scanner includes a light source for projecting a light beam, a deflector for deflecting the light beam, a reflective member for reflecting the light beam toward a target, a contact member, and a pressing member. The reflective member includes a reflective plane and a rear plane opposite the reflective plane. The contact member contacts one of the rear plane of the reflective member and a first lateral plane perpendicular to the reflective plane to position the reflective member in place. The pressing member presses the reflective member against the contact member and includes a first pressing portion to press the reflective plane of the reflective member and a second pressing portion to press a ridge of the reflective member at which the reflective plane and a second lateral plane opposite the first lateral plane and perpendicular to the reflective plane of the reflective member meet.