POSITIVE ELECTRODE ACTIVE MATERIAL FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERIES, AND NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

This positive electrode active material for nonaqueous electrolyte secondary batteries contains a lithium transition metal composite oxide. This lithium transition metal composite oxide is represented by general formula LiMnNiMeOF (wherein 1 ≤ x ≤ 1.2; 0.4 ≤ y ≤ 0.7; 0.1 ≤ z ≤ 0.4; 0 < b ≤ 0.2; 1.9 ≤ a + b ≤ 2.1; and Me represents at least one element selected from among Co, Al, Ti, Ge, Nb, Sr, Mg, Si, P and Sb), while having a BET specific surface area of from 1 m/g to 4 m/g and an average pore diameter of 100 nm or less.