An energy conversion film, which can hold a larger amount of charges by pores in the inside of the film and has high energy conversion performances, is provided, by obtaining a porous resin film with a high expansion ratio without adopting an expansion treatment with a high-pressure gas by forming a thermoplastic resin stretched film having a specified structure. The energy conversion film includes a core layer (A) having specified pores and composed of a thermoplastic resin stretched film including a thermoplastic resin and at least one of an inorganic powder and an organic filler.