[en] In a method of processing radioactive wastes by confining radioactive wastes by using solidified mortars, a resin incorporated mortar layer comprising fine aggregates (mountain sands or river sands having a grain size of less than 5mm), a synthetic resin (acryl resin) and a mixing material (calcium carbonate or silica sand powder) blended at a predetermined ratio is formed on the inner surface of a drum can. Then, after supplying the radioactive waste therein, a mortar filler having portland cement, a water reducer, aggregates and water blended at a predetermined ratio is in the drum can. This can certainly prevent intrusion of underground water and leakage of radioactivity, even if the drum can should suffer from corrosion when it is buried underground thereby enabling to confine them in the can stably for a long period of time. (T.M.)