PURPOSE: To prevent the generation of detection error in vehicle progression direction by providing a vibration imparting mechanism in the gyroscope rotation direction and signal addition function, etc.

CONSTITUTION: When the vibration controller 12 in a CPU 15 outputs a forced vibration command with a vibration mechanism 11 to a gyroscope 4, a forced vibration imparting generation circuit 19 controls the drive of the mechanism 11 and offers the vibration in the forced rotation direction to the gyroscope 4. According to this, analog signal added by sine wave signal to the detection signal is output from the gyroscope 4 to an amplifier 16. This gyroscope output signal after the amplification and passing through an A/D converter 17 is operated in an angular velocity conversion part 13 and converted to angular velocity. Then, an angle conversion part 14 integrates the angular velocity to convert to angle and outputs the angle signal to a vehicle angle output part 18. In this step, each data calculated in the conversion parts 13 and 14 is stored in a memory 15a. Thus, by this control, angle with small error can be obtained.