PURPOSE: To produce an alarm tone when an earpiece or the main body of a hearing aid is forgotten or dropped by supplying an audible frequency signal to a sound circuit when the reception level of a radio wave transmitted from another area is lower than the prescribed value.

CONSTITUTION: For instance, either one of an earpiece 1 and a hearing aid main body 2 is carried with the other forgotten to carry at the spot. In such a case, the output level of a high frequency amplifier 12 is lowered as the user of the hearing aid goes further away from the relevant spot. When the distance between the earpiece 1 and the main body 2 exceeds a certain value and the reception level is lower than the prescribed value, a distance detector 17 produces a distance detecting signal and supplies it to an audible frequency oscillator 18. The oscillator 18 produces the buzzer tone signal of audible frequency. This buzzer tone signal is supplied a sound amplifier 15 and amplified. This amplified signal is converted into a sound by an electroacoustic transducer 16 and outputted. Thus a buzzer tone is generated from the earpiece 1.