PURPOSE: To efficiently utilize the ability of entire communication control modules in an exchange by allowing an another communication module which is free in terms of space to act a packet exchanging processing, even when one communication module which receives a calling request is turned into a congested state.

CONSTITUTION: A distributed packet exchange 11 is equipped with four communication control modules 13-16 which respectively house plural terminals, and the four communication control modules are connected with each other by a common bus 12. Each communication control module is equipped with a storage memory which stores circulation sequence information. congestion reference value, acting capability reference value. Then, when the communication control module which receives the calling request from terminals 17 and 18 is turned into the congested state, an another communication control module which is free in terms of space is allowed to act the packet exchanging processing according to the prescribed circulation sequence. Thus, the ability of the entire communication control modules 13-16 in the exchange 11 can be efficiently utilized.