A pair of stimulating electrodes and a mechanomyography sensor come into intimate contact with a body surface of a muscle, appearing on a back surface of an insulating sheet and being spaced a predetermined distance apart； accordingly, an electrical stimulation position and a position to detect muscle sound are fixed, and the amplitude and frequency of an evoked mechanomyogram MMG can be quantitatively detected without depending on the electrical stimulation position and the muscle sound detection position.
