Abstract: A compactor according to the invention comprises a bowl (2) for receiving the matter that is to be compacted, a crushing head (1) comprising at least one shredding roll (11) that is mounted to rotate on itself and to move upon the surface of the matter when the compacting head is in an active position inside the bowl, and a pressing device comprising a pressure plate (3) for pressing the matter onto a bottom of said bowl when it is in an active position inside the bowl. Configuration means are further provided to move said crushing head and said pressing device, each in turn, into its active position inside the bowl while the other is in an inactive position outside the bowl.