To rapidly and stably recover valuable metals in powder and granular materials at a good yield by supplying a reducing gas at the time of heat treating the powder and granular materials in a vacuum atmosphere.

This device is used to recover the valuable metals such as zinc included in the powder and granular materials, by heating the powder and granular materials under vacuum in a treating chamber 22 existing in a vessel 11 of a hermetic system. The reducing gas, for example, hydrogen, carbon monoxide or a glass mixture composed thereof, is supplied to the treating chamber 22. The reducing gas is liable to be uniformly dispersed over the entire surface of the powder and granular materials and has still a high reducing power and, therefore, the metal oxides, such as zinc oxide, in the powder and granular materials are surely and rapidly reduced to the corresponding metals. Consequently, the formed metal vapors are condensed in a condenser 61 and is recovered. The treating chamber 22 is internally and preferably provided with agitating means for agitating the powder and granular materials.