A small-sized vehicle has an oil control valve for a hydraulically-actuated mechanism of an engine, and provides good cooling of the oil control valve. This filter works by converting the image into its equivalent gray scale. Alternatively, each external electrode includes a plurality of layers including a thick-film electrode formed on the base member, a nickel layer or a nickel alloy layer formed on the thick-film electrode and a tin plating layer formed on the nickel layer or the nickel alloy layer. The embedding unit embeds an electronic watermark into the specified area.