PURPOSE: To produce a palladium powder having a large crystallite diameter and which is not oxidized when burnt by admixing the ion of a specified metal with an aq. Pd ion soln., adding a base to coprecipite the hydroxides of Pd and the metal and reducing the Pd hydroxide.

CONSTITUTION: The water-soluble salt of the metal such as Ca and Mg with the oxide or hydroxide having a lower standard free energy of formation than that of Pd is added to an aq. acidic soln. of Pd nitrate or chloride, a soln. of Pd ion in unboiled water, etc., and uniformly mixed. A base such as NaOH is added to the aq. soln. mixture to coprecipitate Pd hydroxide and the hydroxides of Ca and Mg, and the coprecipitate is filtered off, separated from the filtrate and then dried. The dried material is placed in an electric furnace, the oxygen partial pressure of the atmosphere in the furnace is adjusted, only PdO and Pd(OH)2 are reduced to Pd in the reducing atmosphere, and CaO, Ca(OH)2, MgO and Mg(OH)2 are not reeuced. The mixture is treated with hydrochloric acid, nitric acid or acetic acid to dissolve off the oxides and hydroxides of Ca and Mg, and the Pd powder is separated and recovered.