A vibration pick-up mechanism 4 for picking up bone conducted voice signals from an external auditory canal wall, and a speaker 5 for converting a received electrical signal into a voice are contained in one earpiece 1 to enable a bidirectional speech in a hand free state. A duct 7 communicating between the inside and the outside of the ear is formed to eliminate an increase in the sound pressure in the ear, thereby external sounds may be heard. <IMAGE>
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