An apparatus for selectively preparing a high reactivity polybutene, a midrange reactivity polybutene and a non-reactive polybutene in a single plant, wherein the apparatus comprises: a reactive polybutene polymerization catalyst feeder for polymerization of the high reactivity polybutene and the midrange reactivity polybutene; a non-reactive polybutene polymerization catalyst feeder for polymerization of the non-reactive polybutene; a reactor for polymerizing a reactant including isobutene into polybutene; a neutralization and washing tank for adding water to the reactant discharged from the reactor to eliminate catalyst component from the reactant and neutralize the reactant; a separation tank for eliminating water containing the catalyst component and discharging organic compounds remaining after removal of the catalyst from the reactant; and a C4 distillation tower for distilling unreacted C4 from the organic compounds supplied by the separation tank and discharging the remaining organic compound, wherein the reactive polybutene polymerization catalyst feeder provides a catalyst to yield the high reactivity polybutene and the midrange reactivity polybutene; and the non-reactive polybutene polymerization catalyst feeder provides a catalyst to yield the non-reactive polybutene, and wherein the reactive polybutene polymerization catalyst provided through the reactive polybutene polymerization catalyst feeder comprises a Lewis acid selected from the group consisting of boron trifluoride, boron trichloride, aluminum trichloride, and zinc chloride; and the non-reactive polybutene polymerization catalyst provided through the non-reactive polybutene polymerization catalyst feeder comprises a Lewis acid selected from the group consisting of aluminum trichloride, zinc chloride, and iron chloride. a reactive polybutene polymerization catalyst feeder for polymerization of the high reactivity polybutene and the midrange reactivity polybutene; a non-reactive polybutene polymerization catalyst feeder for polymerization of the non-reactive polybutene; a reactor for polymerizing a reactant including isobutene into polybutene; a neutralization and washing tank for adding water to the reactant discharged from the reactor to eliminate catalyst component from the reactant and neutralize the reactant; a separation tank for eliminating water containing the catalyst component and discharging organic compounds remaining after removal of the catalyst from the reactant; and a C4 distillation tower for distilling unreacted C4 from the organic compounds supplied by the separation tank and discharging the remaining organic compound, wherein the reactive polybutene polymerization catalyst feeder provides a catalyst to yield the high reactivity polybutene and the midrange reactivity polybutene; and the non-reactive polybutene polymerization catalyst feeder provides a catalyst to yield the non-reactive polybutene, and wherein the reactive polybutene polymerization catalyst provided through the reactive polybutene polymerization catalyst feeder comprises a Lewis acid selected from the group consisting of boron trifluoride, boron trichloride, aluminum trichloride, and zinc chloride; and the non-reactive polybutene polymerization catalyst provided through the non-reactive polybutene polymerization catalyst feeder comprises a Lewis acid selected from the group consisting of aluminum trichloride, zinc chloride, and iron chloride. wherein the reactive polybutene polymerization catalyst feeder provides a catalyst to yield the high reactivity polybutene and the midrange reactivity polybutene; and the non-reactive polybutene polymerization catalyst feeder provides a catalyst to yield the non-reactive polybutene, and wherein the reactive polybutene polymerization catalyst provided through the reactive polybutene polymerization catalyst feeder comprises a Lewis acid selected from the group consisting of boron trifluoride, boron trichloride, aluminum trichloride, and zinc chloride; and the non-reactive polybutene polymerization catalyst provided through the non-reactive polybutene polymerization catalyst feeder comprises a Lewis acid selected from the group consisting of aluminum trichloride, zinc chloride, and iron chloride.