Navigation system and lane information display method

A navigation system has a map data acquisition section (21) for acquiring map data including road attributes given to a road, a lane information acquisition section (27) for acquiring lane information defining the number of lanes of roads forming an intersection and also defining roads branching from each lane, a lane direction judgment section (28) for judging the direction of each lane based on the lane information acquired by the lane information acquiring section and on road attributes of roads entering the intersection and of roads exiting the intersection, the attributes being included in the map data acquired by the map data acquisition section, and a lane information display section (29) for displaying the direction of each lane judged by the lane direction judgment section by means of an arrow.