A flexible pillar for a variable geometry flight control surface including upper skin and lower skins includes an elongate shape elastic element having an and at least a first end and a second end. The flexible pillar can be disposed between the upper skin and the lower skin so the elastic element can be fixed to the upper skin at the first end of the flexible pillar and fixed to the lower skin at the second end of the flexible pillar. The flexible pillar has a rigidity along the longitudinal axis of the flexible pillar that is greater than a rigidity of the flexible pillar in shear along a transverse axis of the flexible pillar, the flexible pillar making it possible to obtain a support having a longitudinal direction and able to transmit forces between its ends without, or with little, deformation longitudinally and to be easily deformed in a transverse direction.