The present disclosure provides a positive electrode active material for nonaqueous electrolyte secondary batteries including: a lithium transition metal composite oxide represented by general formula: Lia(Ni1-xCrx)α(Mn1-yTiy)2-α-β-γ-δMgβAlγMδO4 in which 1.00≤a≤1.30, 0.020≤x≤0.200, 0.006≤y≤0.070, 0.450≤α≤0.550, 0≤β≤0.015, 0≤γ≤0.035, and 0≤δ≤0.010, and M represents at least one element selected from the group consisting of Na, K, Ca, Sr, Ba, Ga, Co, Zn, Si, Ge, Zr, Hf, Sn, Ta, Nb, P, Bi, Mo, and W.