An electrochemical cell (1 ) having a proton-conducting membrane (4) is used in the process for the direct electrochemical gas phase synthesis of phosgene. Dry HCl gas and dry CO gas are supplied as the educts to the anode (2) of the electrochemical cell (1). The chlorine radicals formed on anodic oxidation of the HCl gas then react directly with the CO gas to yield phosgene, while the simultaneously formed protons migrate through the membrane (4) to the cathode (3) and are there reduced to hydrogen or, in the presence of oxygen, to water.