An improved planar diaphragm driver includes: a membrane; a first coil, disposed at a first side on a first surface of the membrane; a second coil, disposed at a first side on a second surface of the membrane and electrically connected to the first coil; a third coil, disposed at a second side on the first surface of the membrane and electrically connected to the second coil; and a fourth coil, disposed at a second side on the second surface of the membrane and electrically connected to the third coil. The first and third coils are configured to have a same flowing direction of an electric current at both respective locations thereon equidistant from a central axis of the membrane, and the second and fourth coils also are configured to have a same flowing direction of the electric current at both respective locations thereon equidistant from the central axis.