Disclosed is a reaction device including: a reactor, a heat insulating container housing the reactor, a pipe penetrating a wall of the insulating container to connect the reactor to an outside of the insulating container, wherein the wall of the heat insulating container includes at least two regions each having a different infrared absorptivity, and the region of the wall of higher infrared absorptivity is disposed on the same plane of the wall where the pipe penetrates. Also disclosed are a fuel cell device and an electronic apparatus using the reaction device.