PURPOSE: To transfer an incoming call to other telephone set without a reply and interruption of a conversation or a job when a telephone set receives the call during the important conversation or job by configuring the method such that a transfer connection means applies transfer connection to the telephone set corresponding to a transfer destination number when the telephone set is kept hook-on and the transfer destination number is dialed while a call tone rings.

CONSTITUTION: An exchange 21 is provided with a transfer destination information registration means 22, a transfer destination information retrieval means 23 and a transfer connection means 24, and a transfer key 26 is provided to each of telephone sets A25, B27 connecting to the exchange 21. Furthermore, transfer destination information such as a transfer destination number is registered in advance by the transfer destination information registration means 22. While an incoming call comes to, e.g. the telephone set A25 connecting to the exchange 21 and a call tone rings, the transfer key 26 of the telephone set A25 is depressed or a prescribed time elapses without any reply, the transfer destination information retrieval means 23 of the exchange 21 retrieves the transfer destination information to retrieve the transfer destination number and the transfer connection means 24 applies transfer connection of the call to, e.g. a telephone set B27 corresponding to the transfer destination number.