A nonaqueous electrolyte secondary battery includes a positive electrode comprising a positive electrode material attached to a positive electrode current collector, a negative electrode and a nonaqueous electrolyte, wherein the positive electrode material comprises a positive electrode active material represented by Li.sub.aMn.sub.bNi.sub.bCo.sub.1-2bO.sub.2 (wherein a is 0.ltoreq.a.ltoreq.1.1, and b is 0