The user's personal intention is conveyed to a hearing aid using a method that does not place heavy physical and psychological loads. A hearing aid to be worn by a user for auditory compensation comprises: at least one microphone which converts a sound to an input signal; a hearing-aid signal processing unit configured to generate an output signal from the input signal; a receiver which outputs, as a sound, the output signal generated by the hearing-aid signal processing unit; and a hearing-aid processing control unit configured to generate control information for controlling signal processing, based on a non-audible sound which is made by the user and is hard to hear from outside, wherein, when the hearing-aid processing control unit generates the control information, the hearing-aid signal processing unit is configured to generate the output signal according to the generated control information.