A positive electrode active material for a lithium secondary battery, which is in the form of particles, and comprises a lithium-containing composite metal compound in the form of secondary particles that are aggregates of primary particles capable of being doped and undoped with lithium ions, each of the secondary particles having on its surface a coating layer comprising a metal composite oxide comprising lithium and aluminum, the coating layer having a lithium ion conductivity, wherein the positive electrode active material comprises at least nickel and aluminum as non-lithium metals, wherein the positive electrode active material has a lithium carbonate content of 0.3 % by mass or less and a lithium hydroxide content of 0.3 % by mass or less and satisfies all of requirements to below: [Ave(AR 3 /AR 10)]/[σ(AR 3 /AR 10)], which is a reciprocal of coefficient of variation [σ(AR 3 /AR 10)]/[Ave(AR 3 /AR 10)], is 6.1 or more, wherein: AR is a ratio of a detection intensity of aluminum and a detection intensity of nickel (detection intensity of aluminum/detection intensity of nickel), each measured by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) with respect to surfaces of 20 particles of the positive electrode active material for a lithium secondary battery, AR 3 is AR when the SEM-EDX is performed at an acceleration voltage of 3 kV, AR 10 is AR when the SEM-EDX is performed at an acceleration voltage of 10 kV, [Ave(AR 3 /AR 10)] is an average of values of a ratio of the AR 3 to the AR 10 [AR 3 /AR 10], [σ(AR 3 /AR 10)] is a standard deviation of values of a ratio of the AR 3 to the AR 10 [AR 3 /AR 10], and [σ(AR 3 /AR 10)]/[Ave(AR 3 /AR 10)] is a coefficient of variation calculated from the ratio and the standard deviation, and an average value of AR 3 is 0.025 or more. [Ave(AR 3 /AR 10)]/[σ(AR 3 /AR 10)], which is a reciprocal of coefficient of variation [σ(AR 3 /AR 10)]/[Ave(AR 3 /AR 10)], is 6.1 or more, wherein: AR is a ratio of a detection intensity of aluminum and a detection intensity of nickel (detection intensity of aluminum/detection intensity of nickel), each measured by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) with respect to surfaces of 20 particles of the positive electrode active material for a lithium secondary battery, AR 3 is AR when the SEM-EDX is performed at an acceleration voltage of 3 kV, AR 10 is AR when the SEM-EDX is performed at an acceleration voltage of 10 kV, [Ave(AR 3 /AR 10)] is an average of values of a ratio of the AR 3 to the AR 10 [AR 3 /AR 10], [σ(AR 3 /AR 10)] is a standard deviation of values of a ratio of the AR 3 to the AR 10 [AR 3 /AR 10], and [σ(AR 3 /AR 10)]/[Ave(AR 3 /AR 10)] is a coefficient of variation calculated from the ratio and the standard deviation, and AR is a ratio of a detection intensity of aluminum and a detection intensity of nickel (detection intensity of aluminum/detection intensity of nickel), each measured by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) with respect to surfaces of 20 particles of the positive electrode active material for a lithium secondary battery, AR 3 is AR when the SEM-EDX is performed at an acceleration voltage of 3 kV, AR 10 is AR when the SEM-EDX is performed at an acceleration voltage of 10 kV, [Ave(AR 3 /AR 10)] is an average of values of a ratio of the AR 3 to the AR 10 [AR 3 /AR 10], [σ(AR 3 /AR 10)] is a standard deviation of values of a ratio of the AR 3 to the AR 10 [AR 3 /AR 10], and [σ(AR 3 /AR 10)]/[Ave(AR 3 /AR 10)] is a coefficient of variation calculated from the ratio and the standard deviation, and an average value of AR 3 is 0.025 or more.