To obtain the multi-function telephone set incoming call response system that requires no caller number.

Upon incoming of a call to an office line trunk 1, an exchange central control section 4 detects it and sends an incoming call command to a multi-function telephone set 2. A multi-function telephone control section receives this command through a D channel and controls a display section to conduct call reception display. The display is displayed on plural multi- function telephone sets 2 grouping an extension group and an incoming call tone is sent from an incoming tone transmission section. A talking person recognizes the arrival of an incoming call by the display and an incoming call tone and when no other person can reply, a response key is depressed. The multi-function telephone set control section detects depression of the key through a key section and sends key information to the exchange central control section 4 through the D channel and a multi-function telephone set interface 3. The exchange central control section 4 controls the office line trunk 1 to reply the line receiving the call.