A vehicle-side storage unit of a vehicular device associates and stores an already-traveled route and power consumption when a self vehicle has traveled the already-traveled route, as traveling history data. A vehicle-side control unit of the vehicular device transmits the traveling history data to a center device. A center-side storage unit of the center device stores the traveling history data transmitted from multiple vehicles. A center-side control unit of the center device calculates a necessary electric power for traveling a first route in a guide route, based on the traveling history data of an other vehicle stored in the center-side storage unit, the first route being not overlapping with the already-traveled route of the self vehicle stored in the center-side storage unit.