An object of the present invention is to provide a dialysis apparatus which can prevent the generation of excessive positive pressure in the flow route between the blood pump and the dialysate infusing pump although there would be caused an error in the flow rate of the blood pump and the dialysate infusing pump during the blood-returning process. According to the present invention, there is provided a dialysis apparatus comprising a dialysate infusing line, one end of which being connected to the dialysate introducing line or the dialysate discharging line, the other end-side being branched out at a branch point into two flow routes respectively having a first branch end and a second branch end, the first branch end being able to be connected to the arterial blood circuit or the venous blood circuit, and the second branch end being able to be connected to the tip end of the arterial blood circuit during the blood-returning process, and a dialysate infusing pump arranged on the dialysate infusing line at a connection-side of the dialysate infusing line relative to the dialysate introducing line or the dialysate discharging line from the branch point for supplying the dialysate of the dialysate introducing line or the dialysate discharging line to the first branch end and the second branch end.
