To provide an electromechanical signal selection device which can be miniaturized and highly integrated and which can selectively output only a signal of a predetermined frequency without providing any sensitive vibration sensing mechanism, and electric equipment using the electromechanical signal selection device.A micro-vibrator serving as a resonator is provided. The micro-vibrator can be excited by an external force to excite vibration of the micro-vibrator. A material whose physical property is changed in accordance with a structural change is used as the micro-vibrator. Thus, a sensitive electromechanical signal selection device is obtained.