A nonaqueous electrolyte secondary battery wherein a material capable of occludeing/discharging lithium is used as a negative electrode material and a lithium-trasition metal composite oxide which contains Ni and Mn as the transition metal and has a layered structure is used as a positive electrode material is characterized in that a lithium-transition metal composite oxide having a BET specific surface area less than 3 m2/g and a pH of 11.0 or less when 5 g of the lithium-transition metal composite oxide is immersed in 50 ml of purified water is used as the positive electrode active material.