[en] A magnetic property of Pm as an impurity in PrNi single crystal was investigated by means of the low-temperature nuclear orientation of ^143,144Pm. The angular distribution of γ-ray anisotropies revealed that the direction of hyperfine field experienced by the nuclei lie in the (a, c) plane and made an angle of 60 (5) or 240 (5) with respect to the crystalline c-axis. From the temperature dependence of the anisotropies the strength of the hyperfine field of Pm in PrNi was deduced to be 185(22) T. The hyperfine field of Co at the Ni site of PrNi was found to be less than 4 T. (orig.)