To provide a blood purification apparatus employing a single-needle double-pump method and being capable of automatically discharging a priming solution that has undergone substitution from a blood circuit during blood removal. A blood purification apparatus includes a blood circuit 1 to which an only puncture needle 3 is connectable, a dialyzer 2 that purifies blood flowing in the blood circuit 1, a first blood pump 5, a second blood pump 6, and a control device 17 that allows the blood of a patient to be extracorporeally circulated through the blood circuit 1 by causing the first blood pump 5 and the second blood pump 6 to alternately undergo normal rotation. During blood removal, the control device 17 operates to substitute a priming solution in the blood circuit 1 with the blood of the patient and to discharge the priming solution having undergone the substitution from the blood circuit 1 by causing the first blood pump 5 to undergo normal rotation and the second blood pump 6 to undergo reverse rotation.
