Abstract: This invention provides a wireless transceiver set for a cellular phone including a headset to be put on at a user's ear or head and an adapter unit which is to be connected to a cellular phone and which improves power saving during a stand-by mode in order to extend the life of battery therein longer. The headset includes a microphone, an earphone, a battery and a transceiver circuit to communicate through the adapter unit with a radio frequency. The adapter unit of the wireless transceiver set includes a battery, a transceiver circuit, detection means for periodically detect a radio frequency from the head set, and switch means for cutting off electric power supply from a battery to the circuit in the adapter unit when no radio frequency from the headset is detected.