A number of traveling routes are determined by computations, using a route processor and map information on the basis of current position information and destination information. The rating of the current traffic jam or the predicted traffic jam on each of the traveling routes is recognized based on a traffic jam prediction table and a calendar table obtained by statistically processing VICS data and past traffic conditions in terms of temporal elements. The number of traveling routes to which candidate traveling routes are narrowed is increased as the traffic jam rating is raised. Thus, the number of candidate traveling routes from which a user can select the actual traveling route is increased as the traffic jam rating rises in order to accommodate a situation where secondary traffic jams can take place on any candidate traveling route, thereby providing the user with useful traveling route information and appropriate guidance.