A hemofiltration device capable of surely performing highly-efficient hemofiltration. The hemofiltration device of the present invention is adapted to be implanted in a mammalian body for filtering blood, and includes a blood flow path layer having a blood flow path, a filtrate flow path layer having a filtrate flow path disposed along the blood flow path, and a filtration membrane interposed between the blood flow path layer and the filtrate flow path layer, for filtering the blood flowing through the blood flow path. A filtrate outlet of the filtrate flow path is provided at a position closer to a blood outlet than to a blood inlet of the blood flow path. The blood inlet, blood outlet, and filtrate outlet are provided only on one side or separately on opposite sides of a main body portion in the direction in which the layers are stacked.
