Navigation systems, methods, and programs provide appropriate driving guidance to a driver according to the level of the driving skills of the driver. The navigation systems, methods, and programs identify that the vehicle is in a predetermined specified condition based on information detected by a condition detecting device and detect an actual vehicle control state under the specified conditions based on information detected by an actual state detecting device. The systems, methods, and programs specify an appropriate vehicle control state according to the specified conditions. The systems, methods, and programs determine the level of the driving skills of a driver of the vehicle under the specified conditions based on the actual vehicle control state and the appropriate vehicle control state and output driving guidance according to the determined level of the driving skills under the specified conditions.