In a vehicle driving assistance device, a steering controlling unit estimates lane lines behind a subject vehicle based on lane lines recognized ahead of the subject vehicle and a running state of the subject vehicle, determines whether or not there is a passing vehicle on an adjacent lane based on the estimated lane lines behind the subject vehicle and a solid substance that is detected behind the subject vehicle by a solid substance detecting unit. If there is a passing vehicle a set distance behind the subject vehicle, the steering controlling unit corrects a steering angle of steering control set based on the lane lines ahead of the subject vehicle toward a direction in which the subject vehicle moves wary from the passing vehicle.