A separator and a non-aqueous electrolyte battery

PROBLEM TO BE SOLVED: To prevent electrodes from being damaged or broken by expansion of the electrodes.SOLUTION: A separator for a nonaqueous electrolyte battery includes: a base material having a porous film; and a porous surface layer which is formed on at least one surface of the base material, contains particles and a resin material, and has a rugged surface shape with an arithmetic mean surface roughness Sa from 1.0 μm to 4.0 μm inclusive. In the separator for a nonaqueous electrolyte battery, the surface layer preferably has a compression ratio B/A of 0.4 or greater, where A is the thickness of the surface layer under a load of 3.57 N/cmand B is the collapse amount of the surface layer under a load of 4000 N/cm.