PROBLEM TO BE SOLVED: To provide a hemodialysis apparatus in which an undiluted solution A for dialysis and an undiluted solution B for dialysis are prevented from being mixed almost as the undiluted solution when cleaned, and the corrosion of a metallic portion can be prevented.SOLUTION: A hemodialysis apparatus 2 includes: an undiluted solution A passage 24 for supplying an undiluted solution A for dialysis containing a sodium chloride as the main component and containing calcium in a mixing vessel; and an undiluted solution B passage 25 for supplying an undiluted solution B for dialysis containing a sodium hydrogen carbonate as the main component in the mixing vessel. Undiluted solution A supply piping 7 and undiluted solution B supply piping 8 can be connected to the undiluted solution A passage 24 and the undiluted solution B passage 25, respectively. A bypass passage 41 is provided for bringing the undiluted solution A passage 24 into communication with a waste liquid passage 28. When the undiluted solu
