A direction control plate is fitted near an exhaust aperture of a lamp unit, and a partition plate is fitted so as to surround the front and the bottom of the exhaust aperture. The direction control plate is fitted so as to surround three sides of the periphery of the exhaust aperture in the shape of a letter “U”. Furthermore, the side plate is provided so as somewhat to close the exhaust aperture, and so as to be inclined by an angle θ towards the wall of a case. If a lamp within the lamp unit should break, the direction of scattering of the broken pieces is controlled by this direction control plate, and it is possible to prevent these broken pieces from being scattered to the exterior of the device, since the broken pieces can be made to collide with the partition plate.