An incombustible withdrawing system withdraws an incombustible from a fluidized-bed furnace having a fluidized bed formed therein by a fluidized medium. The incombustible withdrawing system has a mixture delivery path to deliver a mixture of the fluidized medium and the incombustible from a bottom of the fluidized-bed furnace. The incombustible withdrawing system also has a fluidized-bed separating chamber disposed downstream of the mixture delivery path to fluidize the mixture by a fluidizing gas and to separate the mixture into a first separated mixture and a second separated mixture. The incombustible withdrawing system includes a return passage to return the first separated mixture to the fluidized-bed furnace, and an incombustible discharge passage to discharge the second separated mixture to an exterior of the fluidized-bed furnace.