Further, to obtain information regarding traffic situations around the own vehicle, the information input unit 8 is connected with cameras, various kinds of sensors, communication equipment for communication with the outside, and the like mounted on the own vehicle. For example, the information input unit 8 can obtain information of a position, a route, and a travel state of another vehicle through vehicle-to-vehicle communication with the other vehicle traveling, parking, or stopping around the own vehicle and/or can obtain latest traffic information regarding travel situations of other vehicles, road situations, and the like through radio communication with a traffic information center via the internet or public broadcasting.