In a capacitor microphone, a diaphragm is positioned opposite to a fixed electrode for covering inner holes of a ring-shaped support, wherein when the diaphragm is deflected to approach the fixed electrode due to electrostatic attraction upon application of a bias voltage, internal stress that occurs on the diaphragm is canceled by compressive stress that is applied to the diaphragm in advance. The diaphragm is formed using a multilayered structure including a first thin film and a second thin film whose internal stress differs from the internal stress of the first thin film, thus adjusting the total internal stress thereof. The diaphragm can be formed in such a way that a center layer having a single-layered structure is sandwiched between first and second coating layers having controlled residual tensions and resistance against hydrofluoric acid.