Abstract: A galvanic sensor for analyzing gases present in blood includes a duct suitable for being crossed by a flow of gas and provided with an inlet opening and an outlet opening, a reference galvanic element including a container containing an electrolytic solution in which a reference electrode is inserted, and a measuring galvanic element. The container is fixed to the duct and the measuring galvanic element includes a measuring electrode arranged transversally to the axis of the duct and a filiform element having a high capillarity so as to act as a wick. The filiform element is anchored to the container and has a first end contacting the measuring electrode and a second end contacting the electrolytic solution. The measuring element of the galvanic sensor is extremely miniaturized and allows to detect in real time and continuously gases in traces, on the order of parts per million or even lower.