NONAQUEOUS ELECTROLYTE SECONDARY BATTERY LAMINATED SEPARATOR

An aspect of the present invention achieves a nonaqueous electrolyte secondary battery laminated separator which has excellent heat resistance and exhibits an excellent initial battery characteristic when used in a nonaqueous electrolyte secondary battery. A nonaqueous electrolyte secondary battery laminated separator in accordance with an aspect of the present invention includes: a polyolefin porous film; and a porous layer which (i) is disposed on at least one surface of the polyolefin porous film and (ii) includes a heat resistant filler, the porous layer having a surface which has cracks, a ratio of a total area of the cracks to a surface area of the porous layer being 0.15% to 10%.