Provided is a submerged-type, electrosorption-based desalination apparatus for water purification and method, comprising applying a DC voltage of 0.1 to 2.0 volts to a carbon electrode of the reactor to thereby adsorb inorganic ions on the carbon electrode, and reversely applying the same DC voltage having opposite polarity to recycle regeneration solution to the outside of the apparatus or into the treatment tank, thereby enhancing a recovery rate. In addition, in order to improve desalination efficiency, the reactor used in the desalination apparatus may be embodied in various forms of T-shaped, linear type, single, composite, and ion exchange membrane electrodes. Therefore, the present invention may be applied to remove inorganic ions from industrial wastewater, sea water, and brackish water, which contain large amounts of inorganic ions.