Abstract: Projections are formed on front and back surfaces, respectively, of a thin-plate-like protective film at its widthwise opposite ends. Each of the projections is generally trapezoidal as viewed from an end surface side of the thin-plate-like protective film. Even if the projections are misaligned with respect to the projections when the thin-plate-like protective film is wound around a reel, part of a crown portion of each of the inner projections on an exteriorly located part of the thin-plate-like protective film abuts, via the widthwise opposite ends of base film of the tape-like structure, against part of a crown portion of the corresponding outer projection on an interiorly located part of the thin-plate-like protective film. This hinders the widthwise opposite ends of base film of the tape-like structure from being wavily deformed.