To improve desalting efficiency by smoothing the movement of impurity ions from a desalting chamber to a concentration chamber by devising the packing of different types of ion exchangers.

There are provided a method for producing an ion exchange apparatus essentially consisting of the step of making a slurried mixture 4 containing ion exchangers of different types and different specific gravities, the step of forming a layer mainly constituted from low-specific-gravity ion exchangers and a layer mainly constituted from high-specific-gravity ion exchangers by vibrating a container 5 holding the mixture 4, and an ion exchange apparatus (e.g. electrical deionizing apparatus 13) wherein anion exchange membranes A and cation exchange membranes C are alternatingly arranged between electrodes 9a and 9b to alternatingly form concentration chambers 8 and desalting chambers 7, and at least the desalting chambers 7 are packed with a mixture of an anion exchange resin 1 with a cation exchange resin 2, and the desalting chambers 7 have each an anion exchange resin layer 101 mainly containing the anion exchange resin 1 and a cation exchange resin layer 201 mainly containing the cation exchange resin 2.