PURPOSE: To enable communication with a preferred specific trunk line without delay by automatically and quickly responding to the incoming call of the specified trunk line at the time of plural incoming calls.

CONSTITUTION: To the plural incoming calls, by pressing the trunk line selecting button switches 13a of an incoming call response instruction circuit 13 by an operator, most preferred responding trunk line information stored in an incoming call response priority order storage circuit 16 is read. Then, based on the most preferred responding trunk line information, one trunk line within the plural incoming calls to be responded most preferentially is automatically instructed to a trunk line incoming call responding circuit 14 and selected. Thereafter, the incoming call is responded through a handset 15a, a trunk line speech circuit 15 and the trunk line incoming call responding circuit 14 and then the operator performs the communication. By the selection, for instance, the incoming call from an outside can be selected most preferentially and the communication can be performed.