into electrical contact with the centers of the electrode i e vibratory surfaces 1a and 1b of the resonator by inserting the outer peripheries of the terminal strips 2 and 3 into the recesses 4c 1 and 4d 1 on the opposite sides of the frame 4 with the legs 2b and 3b extending outwardly through recesses 4c 2 and 4d 2 respectively the frame 4 is held within an insulating outer shell 5 of synthetic resin which covers the insulating frame 4 entirely likewise the terminal strips 2 and 3 are covered by the insulating outer shell in the preferred embodiment of the present invention the outer wall portions 4c 1 and 4d 1 of recesses 4c and 4d are fused over the periphery of each strip 2 and 3 by means of a heater ultrasonic vibration or the like specifically as shown in fig3 the dashed portion of the lip surrounding the recess 4c 1 is fused to the abutting side of the terminal strip 2 heretofore as previously described piezo electric resonators of this kind have been constructed by inserting a piezo electric resonator in concavity of an insulating frame and inserting terminal strips into the recesses on the opposite sides of the frame which establish on electrical contact with electrode surfaces of the recessed resonator the.