A dialysis apparatus 1 comprises a dialysate circuit 4 that allows a dialysate to flow therein, a blood circuit 3 to be connected to a patient, and a dialyzer 2 connected to the dialysate circuit 4 and the blood circuit 3. Upon an end of a dialytic treatment of the patient, first, air is introduced into a dialysate chamber 2D in the dialyzer 2 to perform backfiltration with around one-third of an inside of the dialysate chamber 2D filled with the dialysate. Consequently, the dialysate in the dialysate circuit 4 flows into the blood circuit 3 via the dialyzer 2, and thus, blood in the blood circuit 3 is returned to the patient. An amount of blood diluted by the dialysate, the blood being returned to the patient, can be reduced compared to the conventional techniques.
