We have measured the polarization of unstable nuclei produced by the technique of ion beam surface interaction at grazing incidence (IBSIGI). A 60 keV 124Cs beam from the on-line mass separator was used. The NMR technique was employed for the observation of the nuclear polarization. A small polarization of 0.22(13)% was observed. The small value was interpreted in terms of the velocity dependence of nuclear polarization, comparing with the results observed with stable nuclei.