To prevent battery exhaustion and improve convenience by on/off- controlling an automatic light drive control device via the combination of engine start/stop signals when the automatic light drive control device is set to the operational state.

When engine stop/start signals are continuously generated by a night transmitter 10 while an automatic lighting switch 4 is set to the on-state, a depression action mode analyzing circuit 19 judges the situation, the second switch circuit 20 is turned on, and an automatic light switch is equivalently turned on. The engine drive signal is fed to an engine drive circuit 16 via a code analyzing circuit 15 to start the engine. An on/off control circuit 3 is operated by the automatic light switch artificially set to the on-state to turn on headlights 7 and tail lamps. The engine drive is stopped, the engine drive circuit 16 forcibly turns off the first and second switch circuits 18, 20, an ignition power source is again turned on, and the on/off control circuit 3 is operated to turn off the lights.