A control unit for generating control signals in response to a communication signal fed from a vehicle, and a plurality of supply units for controlling a supply F of current to respective LEDs in compliance with the control signals generated by the control unit are provided. The control unit changes contents of the control signals in answer to the contents of the communication signal, i.e., to meet to changes of specifications when contents of the communication signal are different every type of a car or every vehicle, whereby standardization of circuit configurations can be achieved.