A spouted bed device of the present invention includes a cylinder which extends vertically; a closing plate which closes a top end of the cylinder; a decreasing diameter member which is formed at a bottom end of the cylinder, has an inside diameter that decreases progressively downward, and has a gas inlet orifice at a bottom end thereof; and a gas discharge nozzle which passes through the cylinder from an inside surface to an outside surface thereof and which discharges gas from a treatment zone enclosed by a top surface of the decreasing diameter member, a bottom surface of the closing plate and the inside surface of the cylinder. The gas discharge nozzle is provided above a spouted bed which is formed within treatment zone.