Tunnel Entrance Specification Device and Method Thereof, Computer Program for Specifying Tunnel Entrance, and Recording Medium on which Computer Program is Recorded

Provided are a device which automatically specifies the elevation and location of a tunnel entrance, and a method thereof. An object entrance for specification of the elevation and/or the location of a tunnel entrance is selected from a map data storage unit. A road link which includes the selected object entrance is designated as an object road link. An elevation of a prescribed region which includes the object entrance is acquired. A boundary is determined between a flat portion and an inclined portion upon the object road link, on the basis of the acquired elevation. The elevation at the determined boundary is specified as the elevation of the object entrance, and/or the determined boundary is specified as the location of the object entrance.