The invention concerns an elementary cell (1) for a fuel cell comprising two electrodes between which an ion exchange membrane (20) is positioned. According to the invention, one of the two electrodes has a threaded surface carrying the ion exchange membrane (20), the assembly formed by this electrode and the ion exchange membrane (20) being able to be assembled by screwing onto a threaded surface belonging to the other of the two electrodes.The invention also concerns a fuel cell provided with a plurality of elementary cells (1).