A screw conveyor, in particular as screw conveyor in a pressing screw device for material to be dried, for example moist or wet waste, consists of a shaft that can be supported on bearings rotatably in the pressing screw device, and at least one spiral screw provided on the shaft to convey the material to be dried in the pressing screw. The spiral screw is formed of at least two elements, such as, for example, a basic element and at least one cover element, and at least one of the elements of the spiral screw is designed exchangeably and removably, respectively.