In a relay communication system, a method and apparatus prevent crossover among call controls in sections and crossover among communication routes in each of the sections. Relay servers relay communication between client terminals. A relay server creates information, and allows a whole of a relay communication system to share the information, which includes: relay group information indicating that the relay servers constitute a relay group; and relay server information indicating a client terminal capable of communicating with the relay server. The relay servers and the client terminals collate identification information of call control, transmitted when the call control is executed for a destination for communication in each section, and identification information of call control, received from the destination for communication in each section when a communication route is established, with each other, and allows the call controls and the communication routes to correspond to each other.