PURPOSE: To obtain a vibrator which makes wide the vacuum degree measuring scope, is small-sized, strong in the impact and excellent in the reliability by making the width of the central part of the vibrator arm smaller than the width of edge part.

CONSTITUTION: A piezoelectric vibrator 1 is set onto a supporting stand 2 composed of a ceramics material, etc., and supported and fixed at the edge part of the supporting part 3 of the vibrator 1 by adhesives 4, etc. A driving electrode is provided at four surfaces of the part of an arm width W1, and the arm width W1 is made larger than an arm width W2 at the central part. For a sensitivity (s) for the vacuum degree of the vibrator 1, the equivalent serial resistance is R1 at the time of the high vacuum and the resistance is R0 at the air pressure, and then, the sensitivity is represented by s=ΔR/R1 (provided that ΔR=R1-R0). Therefore, in such a way, by assembling well the vibrator shape to make small the equivalent serial resistance R1 of the vibrator 1 and the vibrator shape to make large the difference ΔR between the electrode arrangement and the resistance value, the sensitivity (s) for the vacuum degree can be increased.