The method according to the invention makes it possible to use a rather small facility to incinerate, melt and vitrify mixed waste (30) introduced into a reactor (10), using a basket (18) which in turn passes through an airlock (12). Plasma torches (14) burn all of the waste (30) contained in the basket (18). Said waste is then lowered into a molten bath of a furnace (20) with an inductor (24) comprising a container forming a crucible (23). The facility is completed by a combustion gas treatment chain. The furnace (20) can be disassembled, after a treatment series of several baskets (18) of waste (30), to disassemble the crucible-forming container (23) from the furnace (20). The invention is applicable to the treatment of various radiologically contaminated and/or toxic mixed waste.