[en] A nondestructive measuring system has been developed for the measurement of the radionuclide concentration distribution in an aquifer soil sample to measure the radionuclide mobility in the soil layer. In this system, the counting rate distribution of γ-ray is measured by using detectors inserted into the aquifer soil sample, and the simultaneous equations whose coefficient matrix consists of theoretically calculated measuring efficiencies of detector are obtained. The concentration distribution in the aquifer soil sample is determined by solving the simultaneous equations assuming that the concentration distribution decreases exponentially. From the results of function tests, it is found that the radionuclide concentration distribution in an aquifer soil sample can be measured by this system. The report describes the outline of the system and the results of function tests. (author)