To provide a device capable of simply and efficiently producing powder formed with plural-layered metallic oxide films having uniform thickness on its surface.

In this producing device provided with a reaction vessel, a hydrolysis metallic compound supplying means and a stirring means, the reaction vessel 1 for storing solution in which the powder is uniformly dispersed into solvent which can dissolve the hydrolysis metallic compound is provided. A supplying tube 8 consisting of double tubes composed of an outer tube and an inner tube and passing dried inert gas through the outer tube and introducing a prescribed quantity of steam or misty water with a dried inert gas as carrier gas into the inner tube, and a supplying tube 7 for introducing an alcohol base solvent of the hydrolysis metallic compound are provided in the reaction vessel.