A fluidized bed furnace comprising: a fluidized bed having a moving-bed for taking supplied wastes into a fluidized medium and pyrolyzing the wastes into a pyrolysis residue while moving the wastes downwardly together with the fluidized medium, and a fluidized-bed for receiving the fluidized medium and the pyrolysis residue from the moving-bed and combusting at least part of the pyrolysis residue while moving the fluidized medium upwardly, the fluidized medium being circulated between the moving-bed and the fluidized-bed; a moving-bed floorboard having moving-bed gas supply ports formed therein for supplying a moving-bed gas to fluidize the fluidized medium in the moving-bed; a fluidized-bed floorboard having fluidized-bed gas supply ports formed therein for supplying a fluidized-bed gas to fluidize the fluidized medium in the fluidized-bed, the fluidized-bed gas containing oxygen used to combust the at least part of the pyrolysis residue; a moving-bed gas supply means for delivering the moving-bed gas to the moving-bed, the moving-bed gas supply means being capable of regulating a flow rate of the moving-bed gas; and a fluidized-bed gas supply means for delivering the fluidized-bed gas to the fluidized-bed, the fluidized-bed gas supply means being capable of regulating a flow rate of the fluidized-bed gas; the fluidized bed furnace characterized by: a moving-bed temperature detector for detecting a temperature of the moving-bed; a fluidized-bed temperature detector for detecting a temperature of the fluidized-bed; and a controller configured to control the fluidized-bed gas supply means to regulate the flow rate of the fluidized-bed gas supplied to the fluidized-bed to control the temperature of the fluidized-bed in order to cause the temperature detected by the fluidized-bed temperature detector to become a predetermined temperature, and configured to control the moving-bed gas supply means to regulate the flow rate of the moving-bed gas supplied to the moving-bed to control the temperature of the moving-bed in order to cause the temperature detected by the moving-bed temperature detector to be lower than the temperature detected by the fluidized-bed temperature detector by a predetermined temperature. a fluidized bed having a moving-bed for taking supplied wastes into a fluidized medium and pyrolyzing the wastes into a pyrolysis residue while moving the wastes downwardly together with the fluidized medium, and a fluidized-bed for receiving the fluidized medium and the pyrolysis residue from the moving-bed and combusting at least part of the pyrolysis residue while moving the fluidized medium upwardly, the fluidized medium being circulated between the moving-bed and the fluidized-bed; a moving-bed floorboard having moving-bed gas supply ports formed therein for supplying a moving-bed gas to fluidize the fluidized medium in the moving-bed; a fluidized-bed floorboard having fluidized-bed gas supply ports formed therein for supplying a fluidized-bed gas to fluidize the fluidized medium in the fluidized-bed, the fluidized-bed gas containing oxygen used to combust the at least part of the pyrolysis residue; a moving-bed gas supply means for delivering the moving-bed gas to the moving-bed, the moving-bed gas supply means being capable of regulating a flow rate of the moving-bed gas; and a fluidized-bed gas supply means for delivering the fluidized-bed gas to the fluidized-bed, the fluidized-bed gas supply means being capable of regulating a flow rate of the fluidized-bed gas; the fluidized bed furnace characterized by: a moving-bed temperature detector for detecting a temperature of the moving-bed; a fluidized-bed temperature detector for detecting a temperature of the fluidized-bed; and a controller configured to control the fluidized-bed gas supply means to regulate the flow rate of the fluidized-bed gas supplied to the fluidized-bed to control the temperature of the fluidized-bed in order to cause the temperature detected by the fluidized-bed temperature detector to become a predetermined temperature, and configured to control the moving-bed gas supply means to regulate the flow rate of the moving-bed gas supplied to the moving-bed to control the temperature of the moving-bed in order to cause the temperature detected by the moving-bed temperature detector to be lower than the temperature detected by the fluidized-bed temperature detector by a predetermined temperature. a moving-bed temperature detector for detecting a temperature of the moving-bed; a fluidized-bed temperature detector for detecting a temperature of the fluidized-bed; and a controller configured to control the fluidized-bed gas supply means to regulate the flow rate of the fluidized-bed gas supplied to the fluidized-bed to control the temperature of the fluidized-bed in order to cause the temperature detected by the fluidized-bed temperature detector to become a predetermined temperature, and configured to control the moving-bed gas supply means to regulate the flow rate of the moving-bed gas supplied to the moving-bed to control the temperature of the moving-bed in order to cause the temperature detected by the moving-bed temperature detector to be lower than the temperature detected by the fluidized-bed temperature detector by a predetermined temperature.