Traffic-condition notifying device, system and method

A navigation device (100) includes: a congestion-status recognizer for acquiring map information, traffic information about a traffic condition for a mobile body, and accuracy-level information about reliability of a traffic condition of the traffic information relative to an actual traffic condition; and a display controller for making a terminal display (140) display the map information with the accuracy-level information acquired by the congestion-status recognizer superimposed thereon. Therefore, since the navigation device (100) notifies not only the traffic conditions but also the accuracy-level information containing the reliability of the traffic condition, users can be informed of appropriate traffic conditions.