in nonaqueous electrolyte secondary batteries whose positive electrode includes a positive electrode active material containing a lithium - excess transition metal oxide , the charge - discharge cycle characteristics are improved . the positive electrode active material contains a first active material represented by general formula lico x m 1 − x o 2 and a second active material represented by general formula li 1 + y mn 1 − y − z a 2 o & lt ; y & lt ; 0 . 4 , 0 & lt ; z & lt ; 0 . 6 , a is at least one transition metal element and includes at least ni or co ).