An adjustment jig is inserted into an opening and an opening, and a screw provided on an inner lens frame holding a correcting lens is rotated. With the rotation of the screw, a front end of the inner lens frame moves in a direction toward an optical axis or radially outside the correcting lens. With this, the inner lens frame is moved in a direction toward the optical axis or radially outside the correcting lens, and the tilt of the correcting lens is decreased.