A route guiding apparatus provides information for a route using public transportation as an alternative to a vehicular route. In addition to searching for a vehicular route from a current location to a destination, it is determined whether the current location and the destination are within a zone in which public transportation can be used. When the current location and the destination are determined to be within a public transportation zone, a route using public transportation is searched for. Subsequently, the cost of the route using public transportation and the cost of the vehicular route are compared. When the cost of the public transportation route falls within a predetermined limit, the apparatus indicates the public transportation route. The route costs are calculated considering factors such as required travel time and ticket fees. The apparatus may also recommend public transportation when no parking is available near the destination, or based on traffic information concerning the vehicular route.