When output signal of an oscillator are binarized by binarization means, a timing signal for driving a sequence controller for controlling a correction portion is rested temporarily. The process for overwriting the contents of an E2ROM of the correction portion side with an RAM is rested temporarily. This can prevent noise product at the overwriting timing. Binary signals after binarization can be prevented from being varied. The oscillator can be driven stably so as to give an angular speed output with high accuracy.