NOVELTY - An electrochemical gas generator comprises an electrolytic cell (1) with a housing, which is closed by a gas-permeable membrane (2) for exit of a test or calibration gas; cathode (5); anode (4); electrolyte (7); and control unit (6). The cathode and anode are made of precious metal, a mixture of precious metals, or a material containing carbon. The anode is in direct contact with a carboxylic acid or its salt, which acts as a substance to be converted at the anode. The substance to be converted at the anode, is preferably used in form of a pressing (3) deposited on the anode.    USE - As an electrochemical gas generator for producing test/calibration gases such as combustible hydrocarbon gases including alkanes (e.g. ethane) and alkenes (e.g. ethene); useful for functional testing or calibration of gas sensors.    ADVANTAGE - The electrochemical gas generator provides the test/calibration gas such as ethane, through decarboxylation from the carboxylic acid compound at the anode. The electrochemical gas generator for combustible hydrocarbon gases, exhibits very good long-term stability.    DETAILED DESCRIPTION - An electrochemical gas generator comprises an electrolytic cell (1) with a housing, which is closed by a gas-permeable membrane (2) for exit of a test or calibration gas; a cathode (5); an anode (4); an electrolyte (7); and a control unit (6). The cathode and anode are made of precious metal, a mixture of precious metals, or a material containing carbon. The cathode and anode, are in direct contact with the electrolyte. The anode is in direct contact with a carboxylic acid or its salt contained in the electrolyte, where the carboxylic acid or its salt is a substance to be converted at the anode. The substance to be converted at the anode, is preferably used in form of a pressing (3) deposited on the anode, or in the form of a structure pressed together around the anode. The control unit serves as a current source, and is connected to the cathode and anode. The control unit preferably contains a potentiostat. The electrochemical gas generator further comprises a reference electrode in contact with the electrolyte in the electrolytic cell.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of an electrochemical gas generator.    Electrolytic cell (1)    Gas-permeable membrane (2)    Pressing of carboxylic acid or its salt (3)    Anode (4)    Cathode (5)    Control unit (6)    Electrolyte. (7)