PURPOSE: To allow other party to easily recognize the presence of a possessor of a telephone set by applying lighting control to lamps corresponding to telephone sets on a console according to plural kinds of blinking periods and plural kinds of colors through the depression of a presence state setting button.

CONSTITUTION: A main control section 11 makes a call to a key telephone set corresponding to a DSS button 32 of a DSS console 30 when the DSS button is depressed. Moreover, the main control section 11 recognizes the depression of the presence state setting button 24 by a telephone set possessor and up dates the presence state data in a presence state data storage section 15A corresponding to the telephone set possessor according to the presence state corresponding to the depressed button. Then according to the content of the presence state data, the presence state display lamp 23 of the telephone set is subjected to lighting control and a DSS lamp 31 corresponding to the telephone set on each DSS console 30 is subjected to lighting control by plural kinds of blink periods and plural kinds of colors. Thus, the presence state is easily recognized by even other telephone set possessors.