A sludge dehydrating apparatus (200) according to the present invention is configured such that power is provided at opposite sides of a rotating rod (243) of movable disks (230) so that even if the apparatus is comparatively large or is operated at low speed, the rotating rod of the movable disks (230) can be prevented from being deformed. Thereby, the movable disks (230) can be smoothly rotated at the same time, thus enhancing the efficiency of the dehydration operation. Furthermore, because power is provided on the opposite sides both of the rotating rod (243) of the movable disks (230) and of the drive shaft of a screw (210), even if the screw (210) is comparatively long, the drive shaft of the screw (210) can be preventing from bending, thus preventing malfunction of the apparatus such as deformation of a fixed disk or a movable disk.