The electric apparatus includes first and second electrically driven elements operating in response to receipt of electric signals whose polarities reverse periodically at mutually same periods, and a signal outputter outputting the electric signals respectively to the first and second electrically driven elements. The first and second electrically driven elements are arranged such that each of their element surfaces faces toward the element surface of the other electrically driven element or such that their element surfaces face toward a same plane from mutually opposite sides across the plane. The signal outputter outputs the electric signals such that, in each period of the electric signals, a time period in which their polarities are mutually opposite is longer than a time period in which their polarities are mutually identical.