A vehicle drive assistance system is provided, which includes a processor configured to execute a required driving ability estimating module to estimate a driver's required driving ability required for driving a vehicle based on a traffic environment around the vehicle and drive assistance provided to the driver by the vehicle, a current driving ability estimating module to estimate a driver's current driving ability, and a changing module to perform increase processing in which the required driving ability is increased when the current driving ability is higher than the required driving ability.