PURPOSE: To reduce sediment flowing out along with water and to improve the efficiency in treating the sediment by arranging a damming frame in a conveyor belt having a concave section.

CONSTITUTION: An inclined belt conveyor 1 is directed upward. A material to be dehydrated is vibrated by a dehydrating vibrator 3 through the conveyor belt 2 of the inclined belt conveyor 1, squeezed, and dehydrated. The damming frame 4 is arranged in the conveyor belt 2 having a concave section, and formed from a trough part 4a extending in the traveling direction of the conveyor belt 2 and a damming part 4b provided in the lateral direction of the trough part 4a and used for damming water. As a result, the amt. of the material to be treated such as sand flowing out along with water is reduced insofar as possible, and the efficiency in treating sediment is improved.