PURPOSE: To obtain an electrodialyzer which does not require supply of electric power from the outside by forming dialysis elements which form the concd. liquid and deelectrolyte liquid of electrolyte-contg. solns. alternately in a treating tank of the electrodialyzer used for desalting treatment of food, etc.

CONSTITUTION: Sodium chloride solns. are introduced into concentrating chambers C and diluting chambers D through inlets 5 for concd. solns. and inlets 4 for dilute solns. Since the porous aluminum layers 1a and silver porous layers 1b adhered on respective ion exchanging membranes exhibit respectively different potentials and produce potential differences between these layers, electric current flows through short-circuiting parts 3, and both layers maintain polarization states. The Na+ in the chambers D migrate to near the layers 1b and the Na+ and Cl- in the chambers C stagnate in the concentrating chambers respectively by the effect of the ion exchanging membranes. In other words, the behaviors of the Na+ and Cl- in the respective compartments are similar to the behaviors in the prior art and the electrolyte solns. are concd. and diluted without requiring any external power source.