PURPOSE: To provide a sludge dehydrator equipped with a filter cloth belt with a long life, and possible to prevent deterioration in a filter capacity by constructing a sludge dehydrating part by bending a filter cloth belt, and constructing so that sludge comes into contact with both surfaces of the filter cloth belt alternately.

CONSTITUTION: One endless filter cloth belt 30 is engaged with rollers 31, 32 and 33 respectively so that it is possible to run, and a first filter cloth belt part 36 and a second filter cloth belt part 37 are constructed. And, a shear dehydrating part S is constructed between filter cloth belt parts 36 and 37 respectively by reversing the filter cloth belt by 180° in the middle of the endless filter cloth belt. Sludge 1 is squeezed with shearing rollers 35 in the shear dehydrating part S and dehydrated, and peeled off after becoming a dehydrated cake 42. The filter cloth belt parts 36 and 37 are reversed respectively, the sludge 1 comes into contact with the front side and the rear side of each surface of each filter cloth belt part 36 and 37, and since it returns to the original position after making four rounds, the damage of the endless filter cloth belt 30, is reduced.