A car navigation system for predicting an energy consumption of a vehicle along a found route using energy consumption information under a predetermined running condition, the system comprising: an energy consumption prediction means for predicting an energy consumption in each road link in a prediction link list using road link information; and a route search means for seeking a route using, as a link cost, the predicted energy consumption for each road link in the prediction link list calculated; characterized by further comprising: a test cycle characteristic value storage means for storing test cycle characteristic values including theoretical values of an energy consumption per unit mass of a selected one of the fuel and the electric energy of an automotive vehicle under the predetermined running condition, wherein said theoretical values of an energy consumption per unit mass are calculated for a plurality of segments using an equation of motion for the vehicle, wherein said equation of motion accounts for the friction, the gravitational acceleration and the difference between the vehicle speed at the end of one segment and the vehicle speed at the beginning of one segment and by adding the theoretical values for those segments for which the theoretical values are positive; a basic vehicle specification setting means for accepting the input of basic vehicle specifications including at least the weight and the fuel consumption rate of the vehicle involved under the predetermined running condition; and a vehicle energy consumption characteristic calculation means for estimating a vehicle energy consumption parameter in selected one of an engine and a motor of the vehicle, using the test cycle characteristic values and the basic vehicle specifications; wherein said energy consumption prediction means is configured to predict the energy consumption in each road link in the prediction link list using the basic vehicle specifications and the vehicle energy consumption parameter in addition to said road link information, wherein said prediction link list lists links having a high probability of being included in the route and wherein the energy consumption characteristic calculation means sets, as a vehicle energy consumption parameter, selected one of the electric energy consumption and the fuel consumption for idling, and also sets the conversion efficiency from selected one of the fuel combustion energy and the electric energy of the running vehicle into kinetic energy. an energy consumption prediction means for predicting an energy consumption in each road link in a prediction link list using road link information; and a route search means for seeking a route using, as a link cost, the predicted energy consumption for each road link in the prediction link list calculated; a test cycle characteristic value storage means for storing test cycle characteristic values including theoretical values of an energy consumption per unit mass of a selected one of the fuel and the electric energy of an automotive vehicle under the predetermined running condition, wherein said theoretical values of an energy consumption per unit mass are calculated for a plurality of segments using an equation of motion for the vehicle, wherein said equation of motion accounts for the friction, the gravitational acceleration and the difference between the vehicle speed at the end of one segment and the vehicle speed at the beginning of one segment and by adding the theoretical values for those segments for which the theoretical values are positive; a basic vehicle specification setting means for accepting the input of basic vehicle specifications including at least the weight and the fuel consumption rate of the vehicle involved under the predetermined running condition; and a vehicle energy consumption characteristic calculation means for estimating a vehicle energy consumption parameter in selected one of an engine and a motor of the vehicle, using the test cycle characteristic values and the basic vehicle specifications;