A method of producing a porous thin-film-deposition substrate, which has the steps of: placing onto a substrate that has an electrostatic charge on its surface, fine particles with a surface electrostatic charge opposite to the electrostatic charge of the substrate surface, depositing a thin film on the fine-particle-placed substrate, and then removing the fine particles to form fine pores in the thin film; further, a method of producing an electron emitting element, which has the steps of: adding a catalyst metal on a substrate, placing fine particles onto the catalyst-added substrate, depositing a thin film on the fine-particle-placed substrate, then removing the fine particles to form fine pores in the film, and growing needle-shaped conductors on the catalyst metal that is exposed on a bottom face of the fine pore.