PURPOSE: To prevent a test call from being charged in a detailed charging device, by storing it in a subscriber table that the test is executed.

CONSTITUTION: A connection through a path (1) and an outgoing trunk OGT is formed, and an originating connection test is executed. In this case, charging information is gathered similarly to an ordinary originating call, and this information is written in a corresponding area of a trunk memory TMEM. However, when the telephone number and the service class are read out from an area corresponding to the originating subscriber's line in a subscriber table SUBTAB on a basis of information of the storage position of the originating subscriber's line, BCO information indicating the executing of the test is read out also and is written in an area of the trunk memory corresponding to the outgoing trunk OGT, and it is discriminated and recorded that this connection is for the originating test call due to a testing device LTF. Thus, when the account for the telephone rate is made later, the rate related to this connection is eliminated automatically.