NOVELTY - Producing a catalyst-supporting carrier comprises: supplying subcritical or supercritical carbon dioxide to a dissolving tank containing a catalyst precursor; supplying the subcritical or supercritical carbon dioxide in which the catalyst precursor is dissolved to a supporting tank containing a carrier and reducing the catalyst precursor to cause the catalyst to be supported on the carrier; and supplying the subcritical or supercritical carbon dioxide to the supporting tank containing the carrier on which the catalyst is supported to clean the carrier.    USE - The method is useful for producing a catalyst-supporting carrier, preferably alloys such as stainless steel and nickel alloy, ceramics such as alumina mullite, cordierite, and silica, and polymer. The catalyst-supporting carrier is useful for catalysts for purifying exhaust gases from automobiles, catalysts for fuel cells, ammonia synthesizing catalysts for a Haber-Bosch process, hydrogeneration catalysts, and photocatalysts.    ADVANTAGE - The method controls the particle size of catalyst fine particles.    DETAILED DESCRIPTION - Producing a catalyst-supporting carrier comprises: supplying subcritical or supercritical carbon dioxide to a dissolving tank containing a catalyst precursor generated when a catalyst is reduced to dissolve the catalyst precursor in the subcritical or supercritical carbon dioxide; supplying the subcritical or supercritical carbon dioxide in which the catalyst precursor is dissolved to a supporting tank containing a carrier and reducing the catalyst precursor to cause the catalyst to be supported on the carrier; and supplying the subcritical or supercritical carbon dioxide to the supporting tank containing the carrier on which the catalyst is supported to clean the carrier. An INDEPENDENT CLAIM is included for an apparatus for producing the catalyst-supporting carrier, comprising a dissolving tank (21) in which the catalyst precursor generated when a catalyst is reduced is dissolved in subcritical or supercritical carbon dioxide, a supplying unit that supplies the subcritical or supercritical carbon dioxide to the dissolving tank, a supporting tank (31) in which the catalyst precursor dissolved in the subcritical or supercritical carbon dioxide is reduced to cause the catalyst to be supported on a carrier, and a cleaning unit that supplies the subcritical dioxide or supercritical carbon dioxide to the supporting tank to clean the carrier on which the catalyst is supported.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of an apparatus for producing a catalyst-supporting carrier.    Cylinder (11)    Dissolving tank (21)    Supporting tank (31)    Solid-gas separator (41)    Gas-liquid separator. (51)