An object of the present invention is to improve the efficiency of a driving operation of an angular rate sensor employing a tuning fork oscillator made of single crystalline piezoelectric material such as quartz. In order to achieve the object of the present invention, a tuning fork oscillator assembled directly has driver electrodes and detector electrodes provided on a first main surface, a second main surface, an outer surface, and an inner surface of a arm, respectively. The oscillator also has a driver electrode, a monitor electrode, and detector electrodes provided on a first main surface, a second main surface, an inner surface, and an outer surface of the other arm thereof, respectively. A driving voltage is supplied from a driving power source so that the two driver electrodes may be equal in the polarity while the polarity of the driver electrode is opposite to that of the driver electrodes.