The invention adds a hearing aid function to the small portable frequency modulation (FM) radio. The FM radio is a super-heterodyne receiver composed by a FM broadcasting waves (RF), amplifiers, a local oscillator (OSC), a mixer, an IF amplifier, a detector, a voice amplifier (AF), headphones and speakers. To add a hearing aid function to the small portable frequency modulation radio, a FM radio as shown in the abstract figure is manufacturered. A built-in speaker is used as a dynamic microphone (1) for picking up voice signals. In addition, a pre-microphone amplifier (25) is increased, to enlarge the voices picked-up by the microphone. Herein, the high-frequency gain of the audio is inhibited, to reduce the listening barriers caused by the external noise of the frequency. The radio and hearing aids functions are selected by a function switching (20), the selected signal is output to the headphone (27) through the voice amplifier (26) of the original radio, accordingly hearing the voices.