PURPOSE: To remarkably reduce equipment related to charging in a communication network by executing the charging processing of a call in a lower rank office exchange and between the lower rank office exchanges by a higher rank office exchange.

CONSTITUTION: When a subscriber A included in the channel network 11 of the lower rank office exchange 10 executes what people call an intra-office call to the subscriber B included in the channel network 11 of the same lower rank office exchange 10, a virtual connection information sending means 13 in the control device 12 of the lower rank office exchange 10 sends the information of a connected destination to a virtual connection call charging processing means 23 in the control device 22 of the higher rank office exchange 20 through a common signal line 30 as if the intraoffice call is an outgoing connection call to be connected to the higher rank office exchange 20 through a virtual connection line 31 and to be switched and connected by said higher rank office exchange 20. Thus, in respect of the call in the lower rank office exchange 10 as well, the charging processing is executed similarly to the call through the higher rank office exchange 20, and charging information is stored.