A navigation device is provided. The device includes a driving state tracker for tracking a mobile driving state using a current mobile position and RGI (Route Guidance Information) data including driving information on multi-routes from the current mobile position to a destination, and outputting deviation information and the current mobile position when a mobile object is deviated from a route; and a re-routing unit for searching partial routes from a mobile deviation position to each of the multi-routes using the deviation information, the current mobile position and the driving information on the multi-routes, and re-routing a route to the destination using each of the partial routes.