To restrain the vibration of a movable electrode in the direction of Corioli's force to enable high sensitivity detection by applying a.c. voltage having a specified phase difference to a first electrode and a second electrode arranged in such a manner that when voltage is applied, the movable electrodes are respectively subjected to force in the positive and negative directions.

An angular speed detector 1 for detecting the Corioli's force working on a vibrating object includes an electrode group 3 on the surface 2s of a support base plate 2 and a vibrator arranged above that. For example, the electrode group 3 comprises first and second driving electrodes 3a1-3a4, 3b1-3b4 and a detection electrode 3c, and the mass part 4e of the vibrator includes the respective electrodes 4ec, 4e1-4e4. The electrodes are arranged in such a manner that when voltage is applied to the first driving electrodes 3a1-3a4, the vibrator is subjected to force in a designated direction, and when it is applied to the second driving electrodes 3b1-3b4, it is subjected to force in the other direction. An a.c. voltage having π/2 phase difference is applied to the first driving electrodes 3a1-3a4 and the second driving electrodes 3b1-3b4 to detect Corioli's force.