PURPOSE: To obtain a vacuum sensor having a small size, strength to impact and excellent reliability by using a lithium tantalate resonator which is produce by selecting the cutting angle of the resonator to provide min. power sensitivity regardless of the shape of the resonator.

CONSTITUTION: The torsional mode lithium tantalate resonator 1 is supported and fixed at both ends thereof by adhesive agent 4, etc. onto a supporting pedestal 2. The pedestal 2 is made of an insulating material such as ceramics. The resonator is thus made strong to disturbance, more particularly to heavy impact force unlike a cantilever type. The cutting angle of the resonator is selected in the angle range rotating a Y plate by 30W60° around the X-axis as the axis of rotation, by which the min. power sensitivity is obtd. regardless of the shape of the resonator. More specifically, the tensile force of compressive force to the resonator generated by a temp. change is minimized by selecting the cutting angle of the resonator 1.