Aromatic polyamide porous film, process for producing the same and secondary battery

Topic of the invention is providing a film outstandingly, and if the use of the high - temperature for a long time is easy to draw in the performance and porous the aromatic polyamide porous membrane, invention claims a providing the following aromatic polyamide porous membrane with of the preceding topic, namely, one aromatic polyamide porous membrane, using the aromatic polyamide and focus of porous membrane, the is a characterised, wherein at least one surface side, wherein the atomic force microscope comprising the COMPOUND μ m2, range is parts of cross sectional area of formula (10) μ m2 of the surface layer nm thick section of chopped and is parts of cross sectional area of formula (20) μ m2 of the surface layer deposited up with the end to satisfy the following formula. 0.01≤S (10); /S≤0.35≤S(20)/S(10)≤20.