A first mirror has a first reflecting surface convexed in a first direction, a first apex, and a first fan shape. A second mirror has a second reflecting surface convexed in a second direction, a second apex, and a second fan shape. An imaging optical system forms images from a first light emitted from an object, reflected by the first reflecting surface, and subsequently further reflected by the second reflecting surface, and a second light emitted from the object and reflected by the second reflecting surface. The first and second fan shapes have interior angles of 180° or more. A center position of the image sensor is displaced with respect to an optical axis of the imaging optical system. A short side of a photo-receiving surface of the image sensor and a center line of the image of the first or second fan shape are approximately parallel.