Patent ID: 7378753

Claim:
A vehicular automatic light control apparatus comprising: a wiper status detection device for judging a non-rainfall state or a rainfall state based on information about a wiping operation of a windshield wiper of a vehicle; a light sensor for detecting external illuminance; a headlight control device for turning on a headlight if an external illuminance value outside of the vehicle is equal to or lower than a first illuminance threshold value if the non-rainfall state is judged, and for turning the headlight on if the external illuminance value is equal to or lower than a second illuminance threshold value, which is higher than said first illuminance threshold value, if the rainfall state is judged, said headlight control device comprising: an average illuminance value calculator for determining an average illuminance value of the detected external illuminance in predetermined periods when the vehicle is capable of being driven; and a threshold switching device for switching an operating threshold between the second illuminance threshold value and the first illuminance threshold value under different conditions based on whether the headlight is turned on or off; wherein said threshold switching device switches the operating threshold from the second illuminance threshold value to the first illuminance threshold value when the determined average illuminance value is equal to or greater than a predetermined value and the headlight is turned on, and switches the operating threshold from the second threshold value to the first threshold value when the wiping operation of the wiper has not been confirmed for another predetermined period and the headlight is turned off.