PURPOSE: To attain detailed charging for each mail box by sending information between a voice mail device and a private branch of exchange so as to record and output charge information for each mail box when a call is made to an external telephone set after the voice mail device receives a message.

CONSTITUTION: When a voice mail device 1 makes a call via a private branch of exchange 2 and a public telephone network or a private telephone network 4, a mail box number is sent/received between the private branch of exchange and the voice mail device after the transmission and reception of an external line notice destination telephone number and the private branch of exchange stores it. The stored mail box number is transferred to a charging display device connecting to the private branch of exchange, in which charging information such as call information and talking charge are displayed and outputted by each mail box. Thus, each mail box makes a call in the voice mail device 1 by using an external line call reception notice function or the like, since the call information is recorded and outputted by each mail box, detailed charging such as clarification of call management and talking charge is executed for each mail box.