ROUTE SEARCH DEVICE, ROUTE SEARCH METHOD, AND PROGRAM

It is intended to allow an appropriate route search to be performed even with a geographical NW in which accessibility information includes an uninvestigated link. A route appropriateness value calculation unit calculates, for each of a plurality of routes each connecting a departure point and a destination extracted by a route extraction unit and including links connecting individual spots including the departure point and the destination, a route appropriateness value of the route. The route appropriateness value of the route is calculated on the basis of a cost of the route calculated by a cost calculation unit on the basis of a cost representing a degree of passage difficulty which is determined for each of the links with respect to a transportation means on the basis of accessibility information of the investigated link as well as a degree of passage uncertainty representing a possibility that the route cannot be passed through by the transportation mean which is calculated by a passage uncertainty degree calculation unit on the basis of a length of the uninvestigated link included in the route. A route selection unit selects, from among the plurality of routes, the route on the basis of the route appropriateness value of the route.