[en] A batch operation of charging temperature-elevated nitric acid and waste resins (spent ion exchange resin containing radioactive nuclides) into a nuclide separating vessel and stirring, and drawing nitric acid solution after the completion of the stirring are repeated for a number of times, thereby separating radioactive nuclides from spent ion exchange resins. In this case, it is preferred that the temperature of the nitric acid is from 80 to 90degC, and stirring is continued for about 1 hour for 1 batch operation. In particular, it is preferred to use 2-N nitric acid, equalize the injection amount thereof with that of the spent ion exchange resins and repeat the batch operation from 10 to 15times. With such procedures, radioactive nuclides can be separated efficiently from resin wastes having relatively large amount of deposited cruds. In addition, the amount of nitric acid to be used can be reduced. (T.M.)