An angular velocity sensor includes a vibrator vibrating, first and second differential circuits for outputting first and second difference signals, respectively, and a synchronous detector circuit for synchronously detecting the first and second difference signals. First and second sensors outputs first and second detection signals in response to a distortion produced due to an inertial force. The second detection signal has a phase reverse to a phase of the first detection signal. The first difference signal corresponds to a difference provided by subtracting the first detection signal from the second detection signal. The second difference signal corresponds to a difference provided by subtracting the second detection signal from the first detection signal. This angular velocity sensor detects an angular velocity of the vibrator accurately.