A traffic information notification system for use by a vehicle acquires vehicle travel history data, automatically registers, on the basis of the acquired travel history data, at least one route along which the vehicle usually travels, a time at which the vehicle travels along each of the at least one routes, and traffic information associated with each of the at least one routes. The traffic information system compares current traffic information along a registered route to be traveled provided by a traffic information system with the automatically registered traffic information for that registered route to be traveled, and provides a notification, when the current traffic information is substantially different from the automatically registered traffic information, of the substantially different current traffic information.