A microphone unit includes a case; a diaphragm arranged inside the case; and an electric circuit unit that processes an electric signal generated in accordance with vibration of the diaphragm. The case has a first sound introducing space that introduces a sound from outside of the case to a first surface of the diaphragm via a first sound hole; and a second sound introducing space that introduces a sound from outside of the case to a second diaphragm, via a second sound hole. A resonance frequency of the diaphragm is set in the range of ±4 kHz based on the resonance frequency of at least one of the first sound introducing space and the second sound introducing space.