PURPOSE: To reduce the time required for testing all subscriber lines accommodated in an exchange by providing plural subscriber line test equipments in a subscriber line test system for a large scale exchange especially, and operating subscriber test equipments in parallel.

CONSTITUTION: A subscriber line SUB 1 including a telephone set connects to a subscriber line automatic test equipment ALTE 2 via an analog switch ST-L3 called a test link to test a subscriber line insulation resistance and capacitance or the like. Then subscriber line automatic test equipments ALTE A-Z are connected to each of subscriber groups A-Z provided due to a physical limit of the TFT-L3. As a result, then the maximum time of the all subscriber line test time depends on the time testing the subscriber group accommodating a maximum SUB 1 independently of the increase in the tested SUN 1. Thus, the time is reduced regardless of the increase in the ALTE 2.