A headlight controller and a vehicle headlight system including an ADB can include a headlight controller and an optical unit. The headlight controller can include a system controller and a camera photographing vehicles located in a forward direction thereof, and the system controller can be configured to output a control signal to provide various favorable light distribution patterns by using image data output from the camera in accordance with traffic conditions. The optical unit can be configured to emit beam lights using lights emitted from a first and second light-emitting device via a projector lens so that the beam lights can be used as a high beam and a low beam without movable parts. Thus, the disclosed subject matter can include providing vehicle headlight systems that can form various favorable light distribution patterns by utilizing the characteristics of the controller and the optical unit in accordance with the traffic conditions.