Abstract: Provided are an apparatus for modifying textile products and leather products and a method for modifying textile products and leather products suitable for modifying textile products and leather products. The apparatus for modifying textile products and leather products includes a storage tub having an internal space that stores the textile products and/or the leather products, and a spray section that sprays a processing liquid containing a functional substance along with a gas toward the textile products and/or the leather products in the internal space of the storage tub, and the spray section includes a two-fluid nozzle.