A negative-electrode active material comprises a graphite including at least boron and fluorine. The fluorine is disposed at least on a surface of the graphite. A ratio R satisfies 0.5≤R≤1, where R=SBB/SB, and SB denotes a total peak area of a boron 1s spectrum of the graphite obtained by X-ray photoelectron spectroscopy, and SBB denotes a peak area of all spectra each having a peak in a binding energy range of not less than 184.0 eV and not more than 188.5 eV in the boron 1s spectrum.