To search for a nearby interchange by identifying up and down lanes in case of emergency on a freeway.

Positional information, including a plurality of past trace information from a vehicle-mounted device 21, is inputted to a position information- input means 101. A road-type identification means 102 specifies corresponding road data from a map DB 13, based on the position information and identifies whether the road data indicates a freeway. An up/down line identification means 103 specifies the corresponding road data from the map DB 13, based on the position information and identifies the advance direction of the up/down lines according to the continuity of a plurality of position information. An interchange-search means 104 searches for a path in a direction opposite to the specified advance direction from a current position where an emergency has occurred, thus specifying the closest interchange.