The invention is a hearing aid that is mounted on both the left and right ears and generates a notification sound to notify the user to a state change. This hearing aid comprises a first hearing aid and a second hearing aid mounted on the left and right ears, respectively. The first and second hearing aids each have a communication unit, an operating unit, a notification sound generator, and a notification sound generation delay unit. The communication unit performs communication between the first and second hearing aids. The operating unit changes the operating state of the first and second hearing aids. The notification sound generator generates a notification sound when the operating state of the first and second hearing aids changes due to operating of the operating unit. The notification sound generation delay unit controls the notification sound generator of the first hearing aid or the second hearing aid so as to delay by a specific amount the timing at which a notification sound is generated by the notification sound generator in the first hearing aid or the second hearing aid, on the basis of delay time information received through the communication unit.