PURPOSE: To increase the coupling of electromagnetic-mechanical conversion and the energy conversion efficiency, by forming the vertical magnatizing ferro magnetic substance layer on the base such as marcomolecular mold, non-ferrous metal. inorganic substance and electret, and providing it close to the electromagnetic coil.

CONSTITUTION: The ferromagnetic substance layer 2 is made of the material almost vertically magnetized to the surface of the magnetic layer against opposite magnetic field, the magnetic double layer in which one side if N pole and another is S pole is obtained, the alloy such as Gd-Co is formed on the base 1 with the method such as sputtering and vacuum evaporation. As the base 1, the film of polyester about 10 μ or less in thickness is used, and on it, the vertical magnetizing ferro magnetic substance layer 2 is formed as thin film 0.5 μ or less. Since this is very light in weight and has high magnetic flux density, when it is used for speakers, microphones and pick-up's, the impedance matching between mechanical and electrical performance can easily be taken, and excellent coupling and response, excellent sensitivity, linearity and dynamic range can be obtained totally.