The purpose of the invention is to effectively eliminate a blood removal failure, in a blood purification device for performing blood removal via a puncture needle, due to adhesion of a patient's blood vessel to a hole of the puncture needle. The blood purification device 1 has a blood removal line 10 for delivering the blood taken out from a patient P to a blood purifier 20, a blood pump 30 placed on the blood removal line 10, a pressure sensor 40 placed in the blood removal line 10 on a side upstream of the blood pump 30, a transfusion line 50 for supplying a transfusion to the blood removal line 10 on a side upstream of the blood pump 30, a transfusion vessel 60 connected to the transfusion line 50, an opening/closing valve 70 for opening or closing the transfusion line 50, and a control unit 80 for controlling the blood pump 30 and the opening/closing valve 70. The transfusion vessel 60 is placed vertically above the patient P. The control unit 80 opens the transfusion line 50 by means of the opening/closing valve 70 when the pressure measured by the pressure sensor 40 becomes smaller than a predetermined value during operation of the blood pump 30.
