The electrodeionization water producing apparatus comprising a depletion chamber packed with an ion exchange material, the depletion chamber being partitioned by a cation exchange membrane on one side and an anion exchange membrane on the other side, and concentrate chambers installed on both sides of the depletion chamber with the cation exchange membrane and the anion exchange membrane disposed inbetween, the depletion chamber and the concentrate chambers disposing between an anode chamber equipped with an anode and a cathode chamber equipped with a cathode, wherein the concentrate chambers are packed with an organic porous ion exchange material having a continuous pore structure in which the wall made from interconnected macropores contains mesopores with an average diameter of 1 to 1,000 m. The apparatus ensures reduction of electric resistance and does not form scale in the concentrate chamber during long continuous operation.