It is an object of the present invention to provide an electrical deionization apparatus having a novel constitution with excellent deionization efficiency. As means for solving this problem, according to one embodiment of the present invention, there is provided an electrical deionization apparatus having deionization compartments, concentration compartments and electrode compartments partitioned from one another by a plurality of ion exchange membranes between a cathode and an anode, wherein, in the deionization compartments and/or the concentration compartments and/or the electrode compartments, at least one of anion exchange fibrous material layers and cation exchange fibrous material layers are disposed on one another intersecting a water-passing direction.