Abstract: While an information communication is carried out in a high efficiency between an on-vehicle apparatus and a road-sided apparatus, a vehicle-traveling supporting system capable of supporting a traveling operation of a vehicle is provided. Traveling difference information between first traveling condition prediction information of the vehicle predicted based upon map information and vehicle traveling model information, and traveling actual-results information judged based upon sensor information of the vehicle is obtained. Second traveling condition prediction information of the vehicle predicted based upon the same map information and the same vehicle travel model information is obtained. The traveling condition of the vehicle in the next traveling operation is predicted based upon corrected traveling condition prediction information which is obtained by correcting the second traveling condition prediction information with the traveling difference information.