Provided is a method of manufacturing a polymer electret. The method of manufacturing a polymer electrets includes forming a polymer thin film, which includes a block copolymer (BCP) having two or more polymer chains covalently bonded together; forming a nano-structure of the BCP in which a first block formed by first polymer chains that self-assemble together and a second block formed by second polymer chains that self-assemble together are micro-phase-separated, by performing an annealing process on the polymer thin film; forming a porous polymer film with a nano-pore by selectively removing one of the first block and the second block; and charging the porous polymer film.