A communication system, wherein a switch node to which a terminal is connected can be recognized, and a flow table can be updated promptly in accordance with the status of the switch node. The communication system includes: a switch node that operates in accordance with a flow table in which processing content is defined for each of a plurality of flows, and a flow control device that includes a terminal management unit that records, based on a request to set a flow entry from the switch node, information of association between a terminal of a packet source and a switch node to which the terminal is connected, wherein the flow control device refers to the information of association to make the switch node execute a modification or deletion of a flow entry in the flow table.