A multi-film junction structure includes an upper mold having a downwardly extending protrusion formed at a lower surface thereof to allow a recess to be defined in resin that is injected therearound. A first film is attached to a part of the lower surface of the upper mold and a side surface and lower surface of the protrusion, the first film having an extension extended from the lower surface of the protrusion by a predetermined length. A second film is attached to a remaining lower surface of the upper mold and an opposite side surface of the protrusion, the second film having a coupling portion located inside the extension of the first film, wherein the extension is bent upwardly. Additionally, a lower mold is provided having a recess facing the protrusion of the upper mold while being spaced apart from the protrusion, the lower mold defining an injection molding space together with the upper mold for allowing resin to be introduced and injection molded in the space.