According to the 1st aspect of the invention, a navigation system comprises: a storage unit that stores map data managed with links representing smallest road units; a road map display unit that displays a road map based upon the map data; a depressed position detection unit that detects a depressed position on the road map on display; and a route setting unit that extracts a corresponding link corresponding to the depressed position and sets the extracted corresponding link as a route to a destination based upon the map data, and the route setting unit extracts a link adjacent to the corresponding link and makes a decision as to whether or not the adjacent link can be entered from the corresponding link based upon the map data.