In addition to an FM reception antenna element for receiving an FM radio wave and an FM receiver connected to the FM reception antenna element, a mobile object is provided with a first antenna element for receiving a satellite signal, a signal processing unit connected to the first antenna, and a second antenna element connected to the signal processing unit. The illumination optical system includes a first optical member for directing the illumination light toward the reflection type display device, and a second optical member. A product stream is produced containing mercaptans that are removed by use of the cobalt-containing adsorbents of the present invention.