A water-proof air-permeable filter (1) includes: a resin film (2) having formed therein a plurality of through pores (21); and a treated layer (3) having hydrophobicity and oil repellency, and formed on at least one of both surfaces in the thickness direction of the resin film (2) such that the treated layer (3) has openings (31) at positions corresponding to the through pores (21). The through pores (21) each have a predetermined size larger than or equal to 0.01 μm and smaller than or equal to 10 μm, and are uniformly distributed such that a density of the through pores falls within specific limits included in a range from 10 to 1×108 pores/mm2.