An extruder is provided having a transfer region that, in an extruder sleeve, is provided with ribs between which extend flow channels. Disposed opposite the sleeve flow channels are flow channels formed in the extruder screw, and the sum of the cross-sections of the flow channels, when viewed in the direction of extrusion, is shifted toward the sleeve and then toward the screw. The ribs (20) of the extrusion sleeve (12) at the ridges facing the screw (14) have a width that is at least one third, especially at least one half, and preferably approximately 80 to 100% of the width of the flow channels (22). Provided between the ridges of the ribs (20) of the extruder sleeve (12) and of the screw (14) is a gap (24) of more than 0.5%, in particular of about one percent of the diameter of the screw (14).