An in-ear BLUETOOTH® headset antenna for single-ear and double-ear BLUETOOTH® headset. The antenna includes a radiation unit and a ground unit, both utilizing components that make up the headset. The radiation unit is composed of a horn of the BLUETOOTH® headset and a conductive foil attached to the horn surface. One end of the conductive foil is attached to the surface of the headset horn and the other end is connected to the feed point of the RF circuit antenna of the BLUETOOTH® headset. The ground unit includes copper pouring on a main printed circuit board connected to copper pouring a key printed circuit board by a cable. No additional antennas are required, and the in-ear BLUETOOTH® headset antenna reduces costs, saves space, and improves the radiation efficiency of the antenna due to the increased effective radiation area of the antenna.