PURPOSE: To brightly lighten the far front when a bicycle travels at a high speed and the near front when it does at a low speed by controlling the power from a generating section in response to the traveling speed and supplying it to the specific filament of the front illuminating lamp corresponding to said traveling speed.

CONSTITUTION: The AC voltage from a generator 25 is rectified by a rectifier 26. When the voltage is below the zener voltage of a constant voltage diode 27 due to the low speed traveling, the current does not pass through the diode 27, but it turns off the transistor of a control section 28, turns on the transistor of a breaker 32, and then flows into a near front low power consumption bulb 29. In this case, the transistor of the breaker 32 turns off. On the other hand, when the voltage exceeds the zener voltage due to the high speed traveling, the current passes through the constant voltage diode 27, turns on the transistor of the control section 28, turns off the transistor of the breaker 31, turns on the transistor of the breaker 32, and flows into a far front high power consumption bulb 30. As a result, the front can brightly be lightened depending upon the traveling speed.