Disclosed are a catalyst for producing a synthesis gas using a carbon-containing organic compound as a raw material and a process for producing carbon monoxide. The catalyst for producing a synthesis gas is composed of a carrier formed of a metal oxide and at least one catalytic metal selected from rhodium, ruthenium, iridium, palladium and platinum and supported on the carrier and is characterized in that the catalyst has a specific surface area of 25 m.sup.2 /g or less, in that the electronegativity of the metal ion of the carrier metal oxide is 13.0 or less and in that the amount of the supported catalytic metal is 0.0005-0.1 mole %, in terms of a metal, based on the carrier metal oxide. The process for producing carbon monoxide includes a step of reacting a carbon-containing organic compound with carbon dioxide in a pressurized condition to produce a synthesis gas, and a step of concentrating carbon monoxide in the thus obtained synthesis gas and is characterized in that the above-described catalyst is used as a catalyst in the synthesis gas producing step.