The present invention provides an apparatus and a method that is capable of performing continuous coating at a constant coating composition and rate. One embodiment is a deposition apparatus for coating two or more compounds or elements on a substrate, the apparatus comprising: a supply unit for supplying the two or more compounds or elements to a plurality of solid bodies; a heating unit for melting and evaporating the solid bodies supplied from the supply unit to form vapor; a buffer unit, connected to the heating unit, in which the vapor stays and is mixed with previously generated vapor; and a nozzle connected to the buffer unit and having an opening toward the substrate.