NOVELTY - A reaction device (10) comprises a reaction device main body (20) that includes two reaction units (11, 12); container (30) to house the reaction device main body; and two regions that correspond to the reaction units. The regions are provided to the container or internal side of the container. The first reaction unit is set to a temperature higher than that of the second reaction unit. The first region has a higher reflectivity than that of the second region, with respect to heat ray that is radiated from the reaction device main body.    USE - For fuel cell device and electronic apparatus, e.g. lap-top personal computer, mobile phone, personal digital assistant (PDA), electronic notebook, wrist watch, digital still camera, digital video camera, game apparatus, amusement apparatus, or electronic calculator.    ADVANTAGE - The device can maintain temperature difference between reaction units.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) heat-insulating container;    (2) fuel cell device (1) comprising a reaction device main body, a container, two regions, and a fuel cell that generates power by fuel generated by the reaction device main body; and    (3) electronic apparatus comprising an electronic apparatus main body that performs by electricity generated by the power generation cell.    A heat reflective film is provided to substantially entire internal surface of the container, and a heat absorbing film is provided to internal side of the heat reflective film. A product of absorption coefficient and film thickness of the heat absorbing film is approximately 2.3 or more. The heat absorbing film consists of carbon, iron, cobalt, platinum or chromium. The heat absorbing film consists of amorphous semiconductor of tantalum-silicon-oxygen-nitrogen (Ta-Si-O-N) type, and absorption coefficient of the heat absorbing film is approximately 100000/cm or more. The mole ratio Si/Ta is approximately greater than 0.6 to approximately less than 1.0 and N/O is approximately greater than 0.15 to approximately less than 4.1. The heat reflective film consists of gold, aluminum, silver, or copper. The container is made of glass.    DESCRIPTION OF DRAWING(S) - The figure shows a block diagram of fuel cell device.    Fuel cell device (1)    Reaction device (10)    Reaction units (11, 12)    Reaction device main body (20)    Container (30)