A driving aiding system includes a displaying section arranged at a position that can be looked at from a driver's seat of a vehicle, an image picking-up section for picking up an image of a rear portion of the vehicle containing at least a part of a hitch that is provided to the rear portion of the vehicle, and an image processing section for causing the displaying section to display a synthesized image that is obtained by image-processing an image picked up by the image picking-up section. A hitch image of own vehicle in addition to an image of a trailed vehicle and an image of a destination coupler are displayed on a screen of the displaying section. As a result, the relative positional relationship between the hitch and the destination coupler can be checked on the screen and thus the hitch coupling operation can be facilitated.