To provide a multi-layer electret having ultra-high charge stability with excellent thermal resistance so as to attain a work by the surface mount technology and to provide a method of manufacturing thereof.

The multi-layer electret is constructed in such a manner that a fluoroethylene propylene (FEP) film 12 melting-adheres to a surface of a metal plate 11, and a polytetra fluoroethylene (PTFE) film 20 melting-adheres to the surface of the FEP film. The plate manufactured in this way is cooled and charged to provide a multi-layer polymer electret. Further, since the FEP and the PTFE belonging to the same fluoro group mutually have a strong adhesive force, first the FEP film 12 is adhered to the metal plate 11 and the PTFE film 20 is then adhered to the PTFE film with an inferior adhesive force, and the adhered plate is used for a raw material of the electret.