To provide a screw conveyor allowing easy disassembly and assembly in a short time.

This screw conveyor is provided with a casing having a supply port for an object to be conveyed on one end part side and provided with a discharge port for the object to be conveyed on the other end part side, a screw shaft provided turnably between an end plate 13 and a head plate forming each end part of the casing, a pair of bearings 30 attached to the head plate and the end plate 13 to support both end parts of the screw shaft in a condition in which they can be inserted and pulled out, and a driving mechanism transmitting rotation force to the screw shaft. At least either of the head plate and the end plate 13 is detachably attached through a locking member 50, and the screw shaft can be taken out from an opening part formed by removing the head plate or the end plate 13.