1. A filtering setting support device comprising: a logical/physical mapping unit which generates mapping information expressing a path on a configuration of a network from a transmission source node to a destination node for each flow identifier by using a combination of a start node and an end node, based on access policy information which manages flow information composed of a combination of the transmission source node and the destination node included in the network with attaching the flow identifiers and based on physical configuration information of the node included in the network; a filtering point analysis unit which specifies the node in which a plurality of flows are intermingled as a filtering point based on the mapping information, a common format rule generation unit which generates a common format rule that should be set to the filtering point from the flow information including the filtering point; and a common format rule output unit which presents the common format rule to an administrator of the network.