The nonwoven fabric is a blended filament nonwoven fabric including a blend of two types of filaments, wherein the two types of filaments are constituted of thermoplastic resins different from each other, an average fiber diameter obtained by dividing the total value of fiber diameters of the filaments present in the nonwoven fabric by the number of the constituent filaments is 0.1 to 10 μm, and the nonwoven fabric has a specific volume of 12 cm3/g or more; the blended filament nonwoven fabric, wherein the ratio of the number of constituent filaments having fiber diameters of 0.1 to 3 μm is 50% or more of the filaments constituting the nonwoven fabric, and the ratio of the number of constituent filaments having fiber diameters exceeding 3 μm is 50% or less of the filaments constituting the nonwoven fabric; or the nonwoven fabric is produced by a melt-blowing process.