PURPOSE: To prevent the flocculation and the conglutination of an ultrafine powdery material with each other by depositing at least one kind of transition metal component on the fine powdery material having ≤500mμ mean grain size by a precipitation process and molding a fine powdery catalyst for treating hydrocarbon.

CONSTITUTION: A soln. wherein one and more kinds of transition metal compds. are dissolved in a solvent is prepared and a fine powdery material having ≤500mμ means grain size is fully immersed into this soln. to disperse and mix it. A fine powdery catalyst for treating hydrocarbon is produced by adding a precipitant to precipitate the transition metal component and depositing it on the surface of the fine powdery material. As the above-mentioned fine powdery material, a substance group obtained by the gas phase carbonization, in concrete terms, carbon black and thermally decomposed carbon, etc., are used. As the transition metal, a compd. contg. one or more kinds of metals selected from among Cu, Ag, Au, Zn, Cd, Hg, etc., is contained. As the solvent dissolving the transition metal compd., an organic solvent such as alcohol is preferable.