To provide a screw press dehydrator, wherein a bearing is formed at the tip side of a screw without using a bracket, thus the service life of the bearing on the side of a motor is elongated, and further, the rotation of the screw is stabilized.

The screw press dehydrator is constituted so that a screw 2 is rotatably arranged at the inside of a cylindrical screen 1, and further, the tip part of the cylindrical screen 1 is provided with a consolidation zone 3 consolidating impurities carried by a screw 2, wherein the axis part 21 of the screw 2 is extensively provided so as to pass through the compaction zone 3 of the axis part 21 of the screw 2, and the axis part 21 is pivotaly supported by the impurities S compacted in the compaction zone 3.