Disclosed herein is a method of treating radioactive metal waste using melt decontamination, wherein radioactive metal waste, which is generated from nuclear fuel processing facilities or nuclear fuel production facilities, and which cannot be easily treated by surface decontamination because it has a complicated geometric shape, and the surface contamination of which cannot be measured, can be treated by melt decontamination. The method is advantageous in that radioactive metal waste, which cannot be treated by conventional surface decontamination, can be treated, so that radioactive metal waste can be recycled, thereby obtaining economic profits, and further in that a large storage space necessary for cutting and then storing radioactive metal waste is not required, and in that excessive manpower and cost are not required.