Abstract: A capacitor having high stability with temperature comprising a cylindrical metal body, a cylindrical high tension electrode coaxial with the body and placed inside it, and at least two low tension electrodes constrained to remain in contact against the inside wall of the body via an intervening insulating layer, said electrodes being disposed symmetrically about the geometrical axis of the body, said low tension electrodes being held in place by retaining means that allow them to expand freely, the dielectric medium extending between the high tension electrode and the low tension electrodes being a gas or a vacuum, the expansion coefficient .alpha.c of the body being equal to the expansion coefficient .alpha.h of the high tension electrode, and the expansion coefficient .alpha.c of the body material being related to the expansion coefficient .alpha.b of the material of the low tension electrodes by the following inequalities:1.5<.alpha.b/.alpha.c<2.