PURPOSE: To surely reproduce a channel generating a fault.

CONSTITUTION: In the channel testing system equipped with an exchange station 11 to set the first channel corresponding to a speaking party by processing the call of a movable station, radio line control station 13 to allocate a radio channel for speaking by interfacing the radio channel accessed by the movable station and the exchange station 11 and to set the second channel through the first channel between the channel and the speaking party, and judging means 15 to generate test signals and to judge the prioriety of a transmitting state in the block corresponding to the answer signals of the test signals obtained through the prescribed block of these channels, a control means 17 is provided to monitor the transmitting states of the first and second channels and to reproduce the channel at the exchange station 11 and the radio line control station 13 as judged objects when the fault is detected corresponding to the monitored result.