[en] Low temperature nuclear orientation process is the method for polarizing atomic nuclei by placing them under the internal magnetic field or electric field gradient in matters at extremely low temperature, and it is the feature that the orientation can be obtained stably and surely very much. By observing the radiation from the nuclei polarized in this way and nuclear magnetic resonance, the electromagnetic moment of atomic nuclei and the internal fields in matters can be determined. As the index radiation, γ ray has been mostly detected, but for ferromagnetic isotopes, there was not the nucleus suitable to this method. By installing a silicon semiconductor detector in a dilution refrigerator so that nuclear magnetic resonance can be performed by detecting β ray, the magnetic moment of ⁵⁷Ni and ⁵⁹Fe was measured. The preparation of Fe and Ni foil samples, the detection of β ray and γ ray, the experimental setup and the observation of nuclear magnetic resonance are reported. The results of the observed resonance spectra of β ray, the resonance frequency and the magnetic moment of ⁵⁹Fe and ⁵⁷Ni are shown. (K.I.)