An electronic device can include discontinuous storage elements that lie within a trench. The TFT is a multilayer structure including an electrode, a dielectric layer disposed on the electrode, and a metal oxide semiconductor on the dielectric. The insulating structural member 28 is arranged opposite to the floating portion 27a of this earth metal fitting 27 in such a manner that both a concave portion 28a and a convex portion 28b are formed on the insulating structural member 28 to be fitted to the cylindrical-shaped portion 26. The memory tag includes a memory and a transponder, and has an external dimension D. The tapered portion tapers inwardly from the front portion toward the centerline. If the number of errors in at least the second extracted watermark is above a second pre-determined value, the extraction results for the extracted watermarks are combined in order to cumulatively assess the validity of the first extracted watermark and at least the second extracted watermark.