PURPOSE: To obtain a low resonance frequency piezoelectric oscillator featuring an easy manufacture with the microminiature size, high accuracy and high performance each by generating the expansion or contraction distortion via the piezoelectricity of the zinc oxide and also securing excitation of the flection vibration vertical to the thin plate for the oscillator.

CONSTITUTION: Oscillator 7 is formed from the thin plate of the constant-elastic material such as the elinvar or the like and through the photolithography or other methods, and electrodes 2 and 3 excite through lead wires 4∼6. Then zinc oxide film 8 in which the C axis is oriented vertically is provided on the upper surface of oscillator 7. And the positive and negative voltage are applied to electrodes 9 and 10 each, and as a result the downward and upward fields are applied to film 8 at the areas held between electrode 9 and oscillator 7 and between electrode 10 and oscillator 7 respectively with oscillator 7 floating. Then the expansion or contraction distortion is caused by the piezoelectricity of the zinc oxide, and the flection vibration vertical to the thin plate face can be excited to oscillator 7. As result, a low resonance frequency piezoelectric oscillator featuring an easy manufacture can be obtained with the microminiature size, high accuracy and high performance each.