A wet desulfurization apparatus includes a chamber enclosing a space for passing flue gas and including a tubular barrier partitioning the space into an inner chamber region having a first volume and an outer chamber region surrounding the inner chamber region and having a second volume, a flue gas inlet to introduce raw flue gas into the outer chamber region, and a flue gas outlet to discharge desulfurized flue gas from the inner chamber region; a slurry reservoir disposed under the chamber to receive and store an alkaline slurry; first and second sprayers to spray the alkaline slurry into the outer and inner chamber regions, respectively, in order to remove sulfur from the flue gas in the corresponding chamber region; and a demister disposed in the inner chamber region between the second sprayer and the flue gas outlet to remove mist from the flue gas in the inner chamber region.