An adjustable-position load supporting arm (4) comprises a framework having the shape of a deformable parallelogram one free end (5) of which is able to support a load and a jack (12) able to deform the deformable parallelogram, the jack (12) being of the adjustable-pressure type so that the pressure inside the jack (12) is adjustable according to the weight of said load supported by the supporting arm (4). It comprises, at the free end (5), a connecting piece (6) able to support said load and has, in a first configuration, an axis of orientation (A) that is fixed with respect to said fixed link (9a) and, in a second configuration, an axis of orientation (B) that is variable with respect to said fixed link (9a) when said supporting arm (4) shifts position.