After a second liquid is applied to a support and dried, a first liquid is applied thereon. On a film of the first liquid, a third liquid (water) is supplied in droplets using an inkjet-type liquid supply unit. An area supplied with the droplets is referred to as porous area. Next, an organic solvent is evaporated from the film and the droplets are evaporated from the porous area. Thus, a porous film is obtained. The porous film has the porous areas in which a plurality of pores are arranged. Since the droplets are directly formed by an inkjet printing method, a condensation process and a droplet growing process are unnecessary. Thus, the porous film is produced efficiently. Shapes of the porous areas can be changed easily. The porous areas can be formed on the porous film in various patterns.