BLOOD PURIFICATION DEVICE

Provided is a blood purification device 1 comprising: peristaltic liquid supply pumps 24, 64, 74 provided in a blood circuit 2 or a liquid supply line 4; a peristaltic liquid discharge pump 51; a removed water amount detection unit 10 as a water balance amount detection unit that detects a water balance amount of supply liquid and discharge liquid; and a removed water amount control unit 92 as a water balance amount control unit that corrects pump speed of the liquid supply pumps 24, 64, 74 and the liquid discharge pump 51 so that the detected water balance amount matches with a target water balance amount. The removed water amount control unit 92 is constituted so as to perform switching between a first correction condition that corrects the pump speed on every detection of the water balance amount and a second correction condition that corrects the pump speed on the basis of a plurality of detection results of the water balance amount.