An emergency lighting function illumination appliance comprised of a fluorescent lamp tube, a controller, a mains power circuit capable of processing mains electricity for lighting, and a backup circuit that provides for a reserve power source. By integrating these devices, renovation of existent wiring is not required for installation. When mains electricity is normally supplied, an ON-OFF switching approach controls the illumination and extinguishment of the fluorescent lamps, but during mains electricity failures, a power circuit automatically shifts to a backup circuit that furnishes reserve power to provide for emergency lighting. Furthermore, when mains electricity supply is restored, the power circuit is automatically shifted to the mains power circuit such that ordinary lighting function is once again reliant on mains electricity.