A server acquires location information data and direction information data. The location information data indicates a travel path of vehicles with discrete locations. The direction information data indicates a traveling direction at each location indicated by the location information data. The server generates information about a new travel route that does not exist in the map data, based on off-route location information data indicative of a travel path deviated from travel routes existing in map data. The server estimates partial travel routes indicative of parts of the new travel route, based on the off-route location information data and the direction information data indicative of associated traveling directions of vehicles. The server then estimates the shape of the new travel route, based on the estimated partial travel routes.