The surveillance areas of cameras registered on a map having a surveillance region set thereon are projected onto the map. The shortest paths between the cameras registered on the map are searched for. Links between the cameras are determined based on the surveillance areas of the cameras projected on the map and the shortest paths between the cameras detected on the map. Unlike a conventional technique by which link information is manually acquired, this technique does not require a surveillance object to walk around so as to be actually captured by all the cameras, and can be applied even in a case where there is congestion in the surveillance region. Accordingly, the load on the user can be reduced.