An electrochemical gas sensor (10) with a housing (11), with an electrolyte reservoir (12) and with a plurality of electrodes (31, 32, 33). The electrodes (31, 32, 33) include at least one working electrode (31), one counterelectrode (32) and one reference electrode (33). The electrolyte reservoir (12) is filled with a liquid electrolyte (60). All of the electrodes (31, 32, 33) are arranged at or on a common electrode carrier (20).