The hemocatharsis apparatus includes a water removal passage 27 for connecting a dialysate recovery passage 14 and a draining passage 16, and a water removal metering pump P5 in the water removal passage 27 for circulating the cleaning liquid to a closed circuit including a connection passage 5 for connecting the dialysate supply passage 13 and the dialysate recovery passage 14, and a circulation passage 28 for connecting a water supply passage 15 and the draining passage 16 to clean the passages with the cleaning liquid. The hemocatharsis apparatus includes a determination unit for determining appropriateness of the cleaning liquid concentration in the closed circuit. A predetermined amount of the undiluted cleaning liquid is drawn into the closed circuit for circulating purified water and undiluted cleaning liquid in the closed circuit by stopping the water removal metering pump. Upon determination that the cleaning liquid in the closed circuit has appropriate concentration, it is distributed to the water removal passage and the water removal metering pump for cleaning. The hemocatharsis apparatus is capable of preventing damage to the metering pump owing to the high-concentration cleaning liquid.
