An intermediate support (5) for a screw conveyor (1), which has a first shaft (3) rotating about an axis of rotation (X) and defined by a number of segments (3); and a casing (2). The intermediate support (5) has a movable assembly (MA), which is coaxial with and rotates about the axis, of rotation (X), is integral with the first shaft (3), and has a second shaft (6) for connecting two segments (3*), and a bushing (7) fitted onto the second shaft (6); and a fixed assembly (FA), which is coaxial with the axis of rotation (X), and has a supporting body (8) fitted to the bushing (7) and connected rigidly to the casing (2), and a number of annular shields (33) coaxial with the axis of rotation (X) and interposed between the supporting body (8) and the bushing (7).