It is an object of the present invention to provide a blood purifying apparatus capable of avoiding burdensome apparatus arrangement and reducing a burden on an operator while ensuring patient safety. The present invention provides a blood purifying apparatus (80) including a blood pump (81) for feeding blood on an arterial line toward a blood purifier, a dialysate pump (82) for feeding dialysate on a dialysate line toward a blood purifier, a waste fluid pump (83) for feeding out waste fluid in a waste fluid line, a first pump (84) for feeding a substitution fluid in a first line toward a venous line, a second pump (85) for feeding a replacement fluid in a second line toward the venous line, and a controller (90) configured to control driving of these pumps. The controller (90) controls the flow rate of the first pump (84) and the flow rate of the second pump (85) in an interlocking manner.
