A projector includes a lens cover which is slidable relative to a chassis for covering and exposing a projection aperture of a projection lens. A detecting section includes a light emitting portion which projects a light beam and detects the opened state or closed state of the lens cover depending on the absence or presence of the light beam received by a light receiving portion. The light emitting portion and light receiving portion are disposed so that the optical path of the light beam projected from the light emitting portion and received by the light receiving portion intersects the slide direction of the lens cover. A light shielding portion is provided in the lens cover. The light shielding portion is formed in a predetermined width in the slide direction of the lens cover.