There is provided a waterproof hearing aid capable of being worn without caring about the entry of sweat or water even at the time of sweating or bathing. The waterproof hearing aid has a first waterproof film stretchingly provided at the sound inlet of a microphone and a second waterproof film stretchingly provided at the sound outlet of an earphone, a tube (first vent) communicating a microphone chamber formed by the first waterproof film and the microphone with a hearing aid case chamber formed by a hearing aid case, a tube (second vent) communicating an earphone chamber formed by the second waterproof film and the earphone with the hearing aid case chamber, and a porous film (third vent) communicating the hearing aid case chamber with the outside.