To simplify register procedure to PBX by realizing a transfer function to PBX by a group unit.

A first storage part 3 stores a private subscriber number, a group name of the subscriber and subscriber data indicating absence information. The second storage part 4 stores the group name, the numbers of the plural subscribers belonging to the group and a transfer destination number when one of the subscribers is absent. A control part 2 realizes transfer by a group unit, based on the storage contents.