A compacting method and apparatus particularly adapted to compacting hazardous materials, and in particular radioactive waste, in which a container (1, 1', 1", 1"') is compacted inside a compacting skirt (20) by cooperation between a support surface (7) on which the compacting skirt (20) with the container (1') is placed and a compactor (9) disposed faing the support surface (7) and displaceable along a vertical axis inside the compacting skirt (20). According to the compacting method the compacting skirt (20) containing the container (1, 1', 1", 1"') is moved in translation, in particular between a loading station (I) for loading the container (1), a compacting station (II) where the container (1') is compacted, and an unmolding station (III) for unmolding the compacted container (1") and for evacuating the compacted container (1"') downwards.