Patent ID: 7587273

Claim:
A route searching device provided with route terminal points, intersections and branching points as nodes, which comprises links which connect the nodes, a route network database containing the corresponding costs of the links, and a route searching section which uses a label setting method for searching a route from a starting point node to a destination by referring to the route network database, whereby each link is stored in the route network database comprising attribute information which represents a group to which such link belongs; the route searching section calculates a specific upper-order bit in the link cost cumulative value memory of such link as logic “1”, where a potential of a link spreading at a node reached by a user exceeds a potential assumed in route searching if the attribute information on a tracked link is different from that of the link spreading from the node reached when the potential at the node reached is calculated by summing up costs of the links along an outgoing link from the starting point node; and the route searching section outputs a thus-determined route with lowest accumulated cost as a guide route requiring the least number of link attribute changes.