PROBLEM TO BE SOLVED: To provide a method for preventing contamination in piping for dialysis.SOLUTION: The piping 2 for dialysis is connected to a dialysis water supplier 1 by a connection end 21 and also connected to dialyzers 3 by connection ends 23. In order to prevent the contamination in the piping 2 for dialysis, the piping 2 for dialysis includes: a UF film 4 close to the connection end 21 with the dialysis water supplier 1 and UF films 5 close to the connection ends 23 with the dialyzers 3.