PURPOSE: To enable waste to be stably supplied and also to enable hydrogen chloride in exhaust gas to be effectively eliminated by dispensing with the pressure resistant structure design and preventing outside air from being sucked into a furnace.

CONSTITUTION: A gas outlet 62 of a gasifying fluidized-bed furnace 10 for gasifying input waste and discharging noncombustibles and a gas inlet 64 of a produced gas incinerating fluidized-bed furnace 12 for incinerating produced gas of this gasifying fluidized-bed furnace 10 and recovering heat are connected to each other through a produced gas blower 66. Thereby pressure of a freeboard part 30 of the gasifying fluidized-bed furnace 10 and pressure of a freeboard part 34 of the produced gas incinerating fluidized-bed furnace 12 are controlled into the specific value approximately equal to atmospheric pressure, so as to drive the furnaces. Moreover, since an input means for desalting agent for eliminating hydrogen chloride to be generated when waste containing chlorine-based component is gasified is provided on the gasifying fluidizedbed furnace 10, hydrogen chloride in exhaust gas can be effectively eliminated.