Provided is a method for disposal of radioactive waste which can reduce the radiation level until the waste can be reused as landfill or the like and which prevents the leakage of radiation nuclides in the ground. The method includes the following: a primary treatment step of turning the radioactive waste into a radioactive waste (primary treated waste) which has a radiation level equal to or less than a reference value via a radiation shielding agent composed of or predominantly composed of a Ca-based inorganic compound; and a secondary treatment step of heating to melt the primary treated waste and thereafter cooling the same to glass granules, and then sealing radioactive nuclides in the glass body.