A lamp chamber is defined by a translucent cover and a lamp body supporting a light source bulb. A translucent panel is provided within the lamp chamber. A front surface of the translucent panel is half mirror-treated. An upstanding wall portion extends in a fore-aft direction in the lamp body to surround the translucent panel. A plurality of quasi-reflector elements are formed in an inner surface of the upstanding wall portion. The half mirror portion is inclined at a predetermined angle with respect to the upstanding wall portion. When the lamp is off, a reflection of the quasi-reflector elements of the upstanding wall portion is seen in the half mirror portion.