A hearing-aid apparatus using ultrasonic waves is inserted and mounted within an external auditory meatus of an ear, generates an ultrasonic wave band signal by single side band amplitude modulation of a sound signal that is received through a microphone, and outputs the ultrasonic wave band signal and a carrier signal that is used for single side band amplitude modulation as an ultrasonic wave signal to a transfer medium in a predetermined beam direction. Therefore, the ultrasonic wave signal forms a focal area in a damaged hearing organ area, the ultrasonic wave band signal is restored to a sound signal by nonlinear characteristics of a transfer medium in the focal area, and the damaged hearing organ detects the sound signal.