Abstract: In an ACDQ (Automatic Call Distribution Queuing) call transfer method, when an incoming ACDQ call takes place in a telephone set group for exclusively handling ACDQ calls in an ACDQ group which is set by a plurality of telephone sets connected to a plurality of switching centers, it is determined whether all the telephone sets belonging to the telephone set group are busy. The ACDQ call is transferred to the same telephone set group connected to a switching center of a transfer destination which forms the same ACDQ group when all the telephone sets belonging to the telephone set group are busy. Ghost calls as virtual call sounds are originated from the switching center of the transfer destination to at least idle telephone sets in the same telephone set group. The actual ACDQ call is transferred to a telephone set which responds to the originated ghost call first. The ghost calls to remaining telephone sets are released.