PURPOSE: To prevent a so-called chopping phenomenon by which the speech sending signal is interrupted and to improve the speech quality, by detecting the speech receiving level by means of an attenuator having the value depending on the speech sending level in the speech sending mode.

CONSTITUTION: A half echo suppressor is provided with a control suppression switch 2 inserted into a speech sending channel 12, a speech reception detecting circuit 4 which is inserted into a speech receiving channel 13 from a control speech reception loss 3 and the level of the speech receiving signal, a region deciding circuit 5 which detects the calling state from both the speech sending and receiving levels, and a control circuit 6 which controls the switch 2 and the loss 3 from the result of decision. In addition, a variable loss circuit 8 is provided. The loss of the circuit 8 is controlled by the output of a speech sending level detecting circuit 7. Then the speech receiving signal is applied to the circuit 5 via the circuit 8 in a speech sending region. Thus a chopping phenomenon never occurs even if a remote subscriber interrupts the calling since the loss 3 is inserted.