Disclosed is a communication network management method provided with a plurality of communication devices and a management system to transmit packets between a plurality of communication devices through a communication path established by the management system. The management system establishes a communication path for a first service necessitating a guarantee of an availability factor on the basis of a first establishment policy in which communication paths that share the same route even in a part of the communication network are consolidated. The management system establishes a communication path for a second service that does not necessitate a guarantee of an availability factor on the basis of a second establishment policy in which the routes to be used are distributed over the entire communication network. The establishment policy is changed depending on a service type.