The invention is intended to allow a plurality of users to share a single apparatus while securing the privacy of each user. The bra has straps that resemble an article of clothing or match an article of clothing. An acid solution whose primary component is hydrochloric acid and that includes indium is brought into contact with the anion-exchange resin to cause indium to be adsorbed to the anion-exchange resin. The receiving module receives a surrounding sound signal, which is generated by the microphone. 5,863,425; 4,558,479; and 3,822,754. In addition, since the digital circuitry is now separated from the imaging circuitry, it can be formed using a standard CMOS process, which has been optimized for circuit speed and manufacturing cost.