In a non-aqueous electrolyte secondary battery using a layered lithium-transition metal composite oxide as a positive electrode active material, elevated-temperature durability, that is, elevated-temperature storage performance is enhanced without degrading battery capacity. The non-aqueous electrolyte secondary battery includes: a positive electrode including, as a positive electrode active material, layered lithium-transition metal composite oxide containing lithium, nickel, and manganese; a negative electrode active material capable of intercalating and deintercalating lithium; and a non-aqueous electrolyte having lithium ion conductivity, and the lithium-transition metal composite oxide contains a group IVA element and a group IIA element of the periodic table.