A vehicle driver assistance system includes: a steering assist torque generation device configured to generate steering assist torque; a control device configured to control the steering assist torque generation device; and a switch configured to switch a steering mode between a manual steering mode and an automatic steering mode. The manual steering mode is a mode in which steered wheels are steered as a driver operates a steering wheel. The automatic steering mode is a mode in which the steered wheels are steered by the steering assist torque generated by the steering assist torque generation device.