Proposed is a pyrolysis reactor for processing solid municipal and domestic wastes by means of a pyrolytic reaction in the pyrolysis chamber without access of oxygen to the reaction system. The reactor is characterized by containing two waste-feeding screws which have tapered shapes, a gap between the outer surfaces of the threads, are inclined in the vertical plane and converge towards each other in a horizontal plane in the direction from the inlet to the outlet end. The gap is adjustable with diminishing toward the outlet end.