Patent ID: 8520878

Claim:
A microphone unit comprising: an electroacoustic conversion portion that includes a diaphragm vibrated by sound pressure and that converts the sound pressure into an electrical signal; and a first board that is placed and joined on a second board; the second board on which the electroacoustic conversion portion is mounted; a cover portion that includes a first opening portion and a second opening portion formed in one surface of the cover portion and that is arranged on the second board to cover the electroacoustic conversion portion; a first sound passage that leads from an outside through the first opening portion of the cover portion to a first surface of the diaphragm; and a second sound passage that leads from the outside through the second opening portion of the cover portion to a second surface which is a back surface of the diaphragm, wherein the first board includes a groove portion, and the second board includes a first board opening portion communicating with the first opening portion of the cover portion, and the groove portion and a second board opening portion provided opposite to the diaphragm and a locating wall that is provided around the second board opening portion and that comes in contact with the electroacoustic conversion portion to locate the electroacoustic conversion portion.