A carbonic acid diester is produced, at a high reaction rate with a high selectivity and stability, by catalytically reacting carbon monoxide with a nitrous acid ester, preferably in a gas phase, in the presence of a solid catalyst composed of a solid carrier and a catalytic solid material deposited on the carrier and comprising:(1) a first catalyst component comprising at least one member selected from the group consisting of platinum group metals and compounds thereof;(2) a second catalyst component comprising at least one member selected from the group consisting of lanthanide group metals and compounds thereof; andcollecting the resultant carbonic acid diester from a reaction mixture discharged from the catalytic reaction step.