Thermosetting polymer is introduced into a mold at one end thereof to fill said mold. Each of the anode and the cathode includes an electrode substrate, and a catalyst layer is formed on at least one of the electrode substrates and includes at least one proton conductive crosslinked polymer. The device also has a second display wheel having a denotation portion for showing a part of the period other than the part of the period shown by the first display wheel, an opening via which the first display wheel is exposed, and a toothed portion including a plurality of teeth to be driven, and placed overlapping the first display wheel.