A microphone unit including a tubular case having an opened top and an opened bottom, a waterproof film made of metal that has a thickness of 0.01 mm or more and 0.05 mm or less, a hardness of 100 HV or more, a proof stress of 70 N/mm2 or more, and a tensile strength of 350 N/mm2 or more, the waterproof film being fixed to the bottom of the case so as to block an opening part of the bottom of the case, a substrate arranged in the case, a microphone mounted on the substrate, and a sealing member that seals an opening part of the top of the case.