Abstract: A fixed substrate and a displacement substrate are disposed in parallel. The fixed substrate is secured to the inside of a cylindrical casing, and the displacement substrate is elastically supported at the periphery thereof by supporting means. A columnar weight body is secured to the lower surface of the displacement substrate, and a cylindrical inside electrode is formed on the periphery of the weight body. A cylindrical outside electrode is fixed by fixing means at the periphery of the inside electrode. A first capacitance element is constituted by a displacement electrode formed on the upper surface of the displacement substrate and a fixed electrode formed on the lower surface of the fixed substrate. By a change in the capacitance thereof, an acceleration based on longitudinal vibration is detected. In addition, a second capacitance element is constituted by the inside electrode and the outside electrode. By a change in the capacitance thereof, an acceleration based on transverse vibration is detected.