The first occurrence of Judwigite in Japan is noted. The ludwigite occurs as an acicular crystal in forsterite aggregate from Hayama nickel mine, Fukushima Prefecture. In an extremely thin section, it has a strong pleochroism (Z'=dark brown, X'=green) and very high refractive indices. From a chemical analysis, given in Table III, it shows a good accordance with 4MgO•Fe₂O₃•B₂O₃, which has been generally accepted as the formula of ludwigite. When the X-ray powder pattern of the present mineral is compared with that of ludwigite from Hol-Kol, Korea, they show also complete agreement. From these data, the mineral is identified as ludwigite.