A non-aqueous electrolyte secondary battery including a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte, wherein the positive electrode comprises a positive electrode active material comprising a particle of a composite oxide represented by a general formula: LixMe1-y-zMyLzO2. In the general formula, the element Me is at least one transition metal element except Ti, Mn, Y and Zr, the element M is at least one selected from the group consisting of Mg, Ti, Mn and Zn, and the element L is at least one selected from the group consisting of Al, Ca, Ba, Sr, Y and Zr, and 1≦x≦1.05, 0.005≦y≦0.1 (with a proviso that 0.005≦y≦0.5 is satisfied in the case of the element M being Mn) and 0≦z≦0.05 are satisfied. The separator includes a plurality of laminated monolayer films, the plurality of monolayer films each have a microporous structure, and a positive electrode-side monolayer film selected from the plurality of monolayer films which faces the positive electrode is made of polypropylene.