Abstract: An angular velocity sensor, which is able to reduce the variations of driving resonance frequency of the vibrator and to improve the reliability of the sensitivity of detection signal with respect to the angular velocity applied, is provided. The angular velocity sensor comprises an vibrator, and a tuning-fork as the vibrator is formed of a silicone substrate with crystal orientation (100) as its main face, and a side face nearly perpendicular to the driving direction (X direction) of the arm of the tuning-fork corresponds to a crystal orientation where elastic modulus is less dependent on azimuth angle.