In a network, a route which can be uniquely identified is constructed by selecting an arbitrary packet-switching node and an arbitrary transmission line in an arbitrary order from the network. A route memory unit (301) stores data indicating which route is involved in which transmission line within the network. A congested state detecting unit (302) detects a congested state of a transmission line accommodated within its own node. The detected congested state is transmitted to another node by a congested state informing unit (303) as congested state information. A route identifying unit (304) receives the congested state information from the other node and retrieves a route within a corresponding transmission line from the route memory unit (301) to thereby identify the route accommodated within its node. A route control unit (305) carries out control of the congested state of the identified route on the basis of the received congested state information. As described above, since traffic passing the transmission line is classified into "route" and grouped, an object whose congestion is to be supervised is limited and each node can regulated only the traffic passing the transmission line in which the congestion occurred in units of routes. <IMAGE>
