An object is to provide a positive electrode active material for a non-aqueous electrolyte secondary battery that can suppress gelation of a positive electrode mixture paste and can improve stability when a non-aqueous electrolyte secondary battery is manufactured. A positive electrode active material for a non-aqueous electrolyte secondary battery has a hexagonal layered crystal structure, is represented by general formula (1): Li1+sNixCoyMnzMwBtO2+α, and includes a lithium-metal composite oxide containing a secondary particle with a plurality of aggregated primary particles and a lithium-boron compound present on at least a part of surfaces of the primary particles. The amount of lithium hydroxide that elutes when the positive electrode active material is dispersed in water, measured by a neutralization titration method, is 0.01% by mass or more and 0.5% by mass or less with respect to the entire positive electrode active material.