PURPOSE: To attain analysis and countermeasure of a line fault by the maintenance operation person by storing monitor information of a monitored call to a terminal equipment connecting to a telephone exchange and implementing automatic statistic processing.

CONSTITUTION: A monitor means 5 monitors speech quality corresponding to a line group or a line processed by a telephone exchange 2. When a call comes to a designated line or line group, the monitor means 5 and a collection storage means 7 are started to collate whether the call is coincident with number of the call or time condition designated by the maintenance operation person or not when they are coincident, the means 5,7 execute monitoring to the designated line or line group. Then number of the calls is counted and the resulting information is stored depending on the content of monitor information. A statistic output means 9 is started by a request of the maintenance operation person and reads the monitor information obtained by the collection storage means 7 and implements statistic processing to the read information. Then the result of subject to statistic processing is outputted to a peripheral equipment and whether or not the statistic output request of the maintenance operation person is entirely satisfied is discriminated.