A positive electrode active material precursor for a nonaqueous electrolyte secondary battery is provided that includes a nickel-cobalt-manganese carbonate composite represented by general formula NixCoyMnzMtCO3 (where x+y+z+t=1, 0.05≤x≤0.3, 0.1≤y≤0.4, 0.55≤z≤0.8, 0≤t≤0.1, and M denotes at least one additional element selected from a group consisting of Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, and W) and a hydrogen-containing functional group. The ratio H/Me of the amount of hydrogen H to the amount of metal components Me included in the positive electrode active material precursor is less than 1.60. The positive electrode active material further includes a secondary particle formed by a plurality of primary particles that have been aggregated.