A non-aqueous electrolyte secondary battery includes a positive electrode composite material layer containing first positive electrode active material particles containing a lithium nickel composite oxide, second positive electrode active material particles containing lithium iron phosphate, and a conductive material. A ratio of the second positive electrode active material particles in a total mass of the first positive electrode active material particles and the second positive electrode active material particles is not lower than 5 mass % and not higher than 20 mass %. A standard deviation σ representing distribution of an iron element satisfies a condition of 0.28≦σ≦0.52 when distribution of the iron element is determined by conducting area analysis with an electron probe microanalyzer in a cross-section of the positive electrode composite material layer.