An object of the invention is to provide a system properly assisting driving of a vehicle when a vehicle turns at an intersection. An assistance processing executing device (22) which becomes a core of a vehicle driving assistance system is configured to determine driven route (52) of a previous vehicle based on a camera (30) and radar (32), identifying (54) a condition that the previous vehicle turns at the intersection of a driving road where the vehicle exists, and under the condition that the vehicle turns toward the same direction at the intersection, give a steering force (66) to wheels,the steering force being used to assist turning of the vehicle which is along the driven route of the previous vehicle. When the vehicle turns at the intersection, by using the above steering force,a driver can easily make the vehicle follow the previous vehicle to turn at the intersection.