To provide an olivine-based phosphate compound having enhanced electron conductivity and ion conductivity, and a positive-electrode material that exhibits a high discharge capacity and that is excellent in the rate maintenance rate and the discharge capacity maintenance rate.

A phosphate compound has a composition represented by the formula Li_1+a(Mn_1-(q+r)Fe_qM_r)_1+bNb_cPO_4+d, where M is at least one selected from the group consisting of Co and Ni; a, b, c, q, and r are respectively satisfied the following relations, -0.1≤a≤0.1, -0.1≤b≤0.1, 0.0005≤c≤0.08, 0≤q<0.20, and 0≤r<0.20, and 0≤(q+r)<0.20; and d is dependent on the valence of Mn, Fe, M, and Nb, and a, b, c, q, and r, and is the number that achieves electroneutrality.