To improve pedestrian visibility. Provided is a headlight controller connectable to a first headlight and a second headlight spaced apart in a vehicle width direction at the front of the vehicle, the headlight controller including: a rainfall amount detection means installed in the vehicle; and a controller installed in the vehicle, where the controller is connected to the rainfall amount detection means, and the controller carries out control such that when rainfall amount detected by the rainfall amount detection means is equal to or more than a predetermined value, irradiation light from the first headlight becomes relatively darker than irradiation light from the second headlight.
