A dialyzate solution preparing device, comparing a vessel holder (112) for holding a container (102) upside down, the container having a powdery, dialyzate solution preparing preparation filled therein, a cutter (118) movable toward and away from a seal member for the container (102) to cut the seal member, a concentrated liquid storing tank (114a) disposed below the container holding means (112), a mesh member (116) for receiving powder chemical falling from a container disposed substantially horizontal in the upper region of the concentrated liquid storing tank (114a), and a nozzle (120) for applying water to the powdery, dialyzate solution preparing preparation falling onto the mesh member (116) from the container (102) after the seal member has been cut by the cutter (118), so as to form a concentrated dialyzate solution, which is then stored in the concentrated liquid storing tank (114a). The concentrated liquid is fed to a dialyzer (160) while being diluted with diluent water. |