An apparatus for preparing a catalyst for carbon nanotubes using spray pyrolysis and a method for preparing the catalyst are disclosed. The apparatus comprises a plurality of raw material tanks, an agitator to mix raw materials respectively supplied from the raw material tanks, a drier to spray the mixture supplied from the agitator and thus to heat and bake the same, and a storage to store a dried material discharged from the drier. The method comprises supplying a plurality of raw materials, mixing the raw materials with one another, spraying the raw material mixture in a liquid state and drying the same at a high temperature, and storing a catalyst generated in the drying process.