Relates to a fluidized bed apparatus for the production of rice hull derived silica through the synthesis gas and chaff gasification / combustion reaction using rice husk gasification process, introducing a feature in the peripheral having an air oxygen supply pipe for supplying a heat source to the upper chamber, the combustion for heating fed to the heat source in order to run the reaction first gasification chamber, running the gasification reaction for heat absorbing and a second gasification chamber and the second gasification chamber and distribution plates for defining the introduction chamber to comprise the first gasification chamber the dispersion is board mounted to the second gasification fluidized double tube reaction chamber having a gas supply pipe for fluidizing the fuel supplied to the chamber, is attached to the upper end of the first gasification chamber, the chamber cap to downwardly discharge the gasified substances to both sides, a cap for moving the position of the chamber cap the part, the second gasification chamber and the compartment while the solid components of the gasification material space and the second a central part of claim so as to discharge into the gasification chamber 1, the gasification chamber, the outer surface a certain distance apart provided compartment plate discharge chamber, that the in accordance with the first gasification chamber and the circulation of the combustion and the fuel in the second gasification chamber controls the height condition, supply state of the fluidizing gas in the supply condition, the chamber cap of the air or oxygen to provide a configuration including a control device, it can produce the amount of heat of the synthesis gas by controlling the particle spacing of the gasification material circulation in the combustion process.