A non-aqueous electrolyte secondary battery includes: a pressure-type current interrupt device (30) arranged in a conductive path, for interrupting the conductive path when an internal pressure exceeds a working pressure; a non-aqueous electrolyte; and a positive electrode composite material layer (10b). The non-aqueous electrolyte contains a gas generation agent that generates a gas in an overcharge region, and the positive electrode composite material layer contains a first positive electrode active material particle including lithium iron phosphate, and a second positive electrode active material particle including lithium-nickel composite oxide. A ratio of the first positive electrode active material particle to a total mass of the first positive electrode active material particle and the second positive electrode active material particle is 5% by mass or more and 20% by mass or less.