Images taken by a plurality of cameras mounted on a vehicle are combined and an image of the surrounding area is developed, in a plane, around a vehicle display portion. The vehicle display portion shows an illustration border line indicative of the outer shape of the vehicle. The outline of the vehicle indicated by the illustration border line is drawn slightly larger than the outer shape of the actual image of the vehicle. This allows margin areas to be formed between the vehicle and its surroundings, thus reducing the possibility of a collision with an obstacle during driving.