A non-aqueous electrolyte secondary battery including a positive electrode, a negative electrode, a non-aqueous electrolyte, and a separator, wherein the positive electrode includes a positive electrode current collector and a positive electrode material mixture layer formed on one or both sides of the positive electrode current collector, the positive electrode material mixture layer has a thickness greater than 80 μm per side of the positive electrode current collector, the positive electrode material mixture layer includes a positive electrode active material, the positive electrode active material is composed of secondary particles formed by aggregation of primary particles, the secondary particles have an average particle size of 6 μm or less, and, when diffraction-line integrated intensities of the (003) plane and the (104) plane in an X-ray diffraction chart of the positive electrode material mixture layer are I003 and I104, respectively, the ratio I003/I104 of the integrated intensities is 1.1 or more.