Abstract: Mechanism for an aneroid barometer comprising, in a support 2, a primary lever 4 whose center is in contact with the cell 3, the axis of rotation 40 of this primary lever being located at the periphery of the support, an endless screw 5 equipped with a helicoidal ramp 51 made integral with the lever 4 via a bridge 7, a secondary lever 6 whose axis of rotation 60 rests on the free end 41 of the lever 4, the free end 61 of this lever 6 ending in a point 62 which acts permanently on the helicoidal ramp 51. A single spring 8 bears on the support 2 and keeps both the lever 4 in contact with the cell and the secondary lever on the primary lever.