Abstract: A wood working machine for wood like pulp wood, saw timber or similar elongated wood parts comprises a trough designed like a tunnel. The trough has a feeding in end and a feeding out end for the wood. Rotors, each provided with helical threads on its jacket surface, are arranged in the trough for the purpose of at least partially debarking the wood. The machine performs a method where the wood during the working is taken by the rotors (6) from a portion of the trough (2) on a first level to a side-displaced portion of the trough on a second, higher level. The wood falls down to the lower level whereby tumbling of the wood is brought about at the same time as a further working of the wood is conducted. The wood during the working is taken by the rotors from the feeding in end (3) of the trough (2) to its feeding out end (4).