Provided is a positive active material for a nonaqueous electrolyte secondary battery which includes a lithium transition metal composite oxide. A molar ratio (Li/Me) of Li and a transition metal (Me) that form the lithium transition metal composite oxide is more than 1. The transition metal (Me) includes Mn, Ni and Co. The lithium transition metal composite oxide has an α-NaFeO2-type crystal structure, an X-ray diffraction pattern attributable to a space group R3-m, and a full width at half maximum (FWHM (104)) for the diffraction peak of the (104) plane at a Miller index hkl in X-ray diffraction measurement using a CuKα ray of 0.21° or more and 0.55° or less. A ratio (FWHM (003)/FWHM (104)) of a full width at half maximum for the diffraction peak of the (003) plane and the full width at half maximum for the diffraction peak of the (104) plane at the Miller index hkl is 0.72 or less. Particles of the lithium transition metal composite oxide have a peak differential pore volume of 0.33 mm3/(g·nm) or less.