PURPOSE: To obtain a small-sized vacuum sensor which is tolerant to a shock and has superior reliability by using a crystal resonator by selecting the cutting angle of the resonator which provides minimum force sensitivity regardless of the shape of the resonator.

CONSTITUTION: The torsional-mode AlPO4 resonator 1 has both is end parts 3 supported fixedly on a support pedestal 2 with an adhesive 4, etc. The support pedestal 2 is made of an insulating material such as ceramic. Consequently, this resonator becomes tolerant to disturbance, specially, impact force unlike a cantilever type. Then, the cutting angle of the resonator 1 is selected within such an angle range that a Y plate is rotated by 10W50° around an X axis as an axis of rotation, and consequently the minimum force sensitivity is obtained regardless of the shape of the resonator. Namely, stress to the resonator 1 originating from temperature variation is minimized by selecting the cutting angle of the resonator 1.