[Object] An amount of content water removal from blood can be controlled with high precision based on easier control and mechanism.[Solution] A hemodialysis apparatus 1 includes a dialyzer 10, a quantitative vessel 13 including a displaceable partition wall 52 which partitions the inside of the quantitative vessel 13 into a first chamber 50 and a second chamber 51, a storage vessel 14 which stores a dialysate, a dialysate exchange circuit 15 which supplies the dialysate to the first chamber 50, and discharges a waste dialysate in the second chamber 51 to the outside by the consequent displacement of the partition wall 52 to the second chamber 51 side, a dialysate supply circuit 16 which supplies the dialysate in the first chamber 50 to the dialyzer 10, and discharges the waste dialysate from the dialyzer 10 to the second chamber 51 by the displacement of the partition wall 52 to the first chamber 50 side, and a dialysate storage circuit 17 which supplies the dialysate in the first chamber 50 to the storage vessel 14 by the displacement of the partition wall 52 to the first chamber 50 side.
