PURPOSE: To obtain a vibrator for the vacuum sensor which is small-sized and excellent in the reliability by making the width near the tuning fork base wider than the arm width of the tuning fork tip part, and arranging the exciting electrode only to the wide part near the tuning fork base.

CONSTITUTION: For the tuning fork arm width of a tuning fork type piezoelectric vibrator 1, a width W1 near the tuning fork base is made thicker than an arm width W2 of the tuning fork tip part, and the electrode is arranged only at part of the width W1 near the tuning fork base. Namely, at the main surface, exiting electrodes 4 and 5 are arranged at the side surface, and further, the exciting electrode is respectively arranged at the rear surface facing to the exciting electrodes 2 and 3, and also at the side surface facing to the exciting electrodes 4 and 5. In respective electrodes arranged to the tuning fork arm, adjoining electrodes are arranged so that they can be different electrodes, and by impressing the alternating voltage to electrode terminals 6 and 7, the bending vibration can be caused.