To attain reduction of the number of assembling man-hours, lightening of weight, and reduction of a cost, by simplifying a circuit system of a rear lamp.

As a rear lamp 11, 12, a lamp of single filament is used, also in a circuit connecting filaments 13, 14 and a battery 15, a fuse 17 is interposed from a battery side, also the downstream of the fuse is made to branch, a parallel circuit 18 is provided. In one circuit, a stop lamp switch 19 is interposed, also in the other circuit, a tail lamp relay 20 on/off turned by a tail lamp switch 22 and a tail resistor 21 are interposed, the parallel circuit is connected to the filament of the rear lamp. In the case of the stop lamp switch turned on, a current is allowed to flow in the rear lamp without through the tail resistor, on the other hand, in the case of the tail lamp switch turned on, a current is allowed to flow in the rear lamp through the tail resistor, the rear lamp is lighted.