There is provided a porous polyimide film in which the pore distribution width A represented by the following formula is 1.15 or less, the average pore diameter is within a range of 0.50 μm to 3.0 μm, and the air permeation speed is 30 seconds or less: A=(D84/D16)1/2 wherein D16 is the pore diameter at 16% cumulation from the small diameter side of pores, and D84 is the pore diameter at 84% cumulation from the small diameter side of pores.