Abstract: A precursor for a lithium secondary battery positive electrode active material containing at least a nickel atom, in which, in a volume-based cumulative particle size distribution curve that is obtained by laser diffraction type particle size distribution measurement, a particle diameter (µm) at which a cumulative volume fraction from a small particle side becomes 10% is defined as D10, a particle diameter (µm) at which the cumulative volume fraction from the small particle side becomes 30% is defined as D30, a particle diameter (µm) at which the cumulative volume fraction from the small particle side becomes 50% is defined as D50, a particle diameter (µm) at which the cumulative volume fraction from the small particle side becomes 70% is defined as D70, and a particle diameter (µm) at which the cumulative volume fraction from the small particle side becomes 90% is defined as D90, the D10, the D30, the D50, the D70, and the D90 satisfy (1) to (3) below. D 50 - D 10 / D 30 ? 0.

Abstract: A precursor for lithium secondary battery positive electrode active materials containing at least nickel, in which the following formula (1) is satisfied. 0.20?Dmin/Dmax??(1) (in the formula (1), Dmin is a minimum particle diameter (?m) in a cumulative particle size distribution curve obtained by measuring the precursor for lithium secondary battery positive electrode active materials with a laser diffraction-type particle size distribution measuring instrument, and Dmax is a maximum particle diameter (?m) in the cumulative particle size distribution curve obtained by the measurement with the laser diffraction-type particle size distribution measuring instrument.