Navigation system and navigation apparatus used in the navigation system

A navigation system includes a navigation center and a plurality of navigation apparatuses each of which has a data storage that stores various information. In this navigation system, data (coordinate data of each of traveling intersections) concerning a recommended route is transmitted from the navigation center to the navigation apparatus, and then route guidance is carried out in the navigation apparatus using the data received from the navigation center. In the case where the navigation apparatus has intersection data for an intersection specified by the data received from the navigation center, the navigation apparatus extracts the intersection data for the intersection from the data storage. Further, in the case where the navigation center does not have intersection data for an intersection specified by the data received from the navigation center, the navigation apparatus establishes the intersection as a newly-built intersection on the recommended route. Then, the navigation apparatus produces route guidance data (which is used for providing route guidance to a user) using the extracted intersection data, and/or intersection data concerning the established newly-built intersection in addition to the information in the data storage.