Iron compound particles comprise a β-FeOOH crystal phase and a metal element other than Fe with which the β-FeOOH crystal phase is doped, whereinthe metal element other than Fe is at least one metal element selected from the group consisting of elements of Al as well as 3d and 4d transition metals belonging to periodic table Groups 4 to 12 other than Fe,an atomic ratio of the metal element other than Fe to the Fe element (metal element other than Fe/Fe element) is 0.001 to 0.5, andthe iron compound particles satisfy at least one of the following requirements (A) and (B): (A) having a crystallite diameter of 1 to 60 nm when measured by X-ray diffraction; and (B) having an average particle diameter of 1 to 600 nm when measured by dynamic light scattering in a solvent.