To provide a technique for allowing a search for a route taking into account turnarounds in the entire way from a point of departure to a destination. A route search system includes a node obtaining part that obtains nodes present between a point of departure and a destination of a vehicle; a passage cost obtaining part that obtains a passage cost of a road section between the nodes and the passage costs of intersections represented by the nodes; and a route searching part that searches for a route with the smallest sum of the passage costs between the point of departure and the destination, and the route searching part sets the passage cost for a case of making a turnaround, for all of the intersections included in a candidate for a route from the point of departure to the destination, based on the road section traveled after the turnaround.