The present invention relates to a device for adjusting the vertical position of the boot support holder (P) for a ski fastening system comprising a base (E) and a plate (Cr) forming a cover, said support holder comprising a vertically movable support element (1) and at least one ramp (11) cooperating by contact with a wedge (2) that can move in longitudinal translation under the action of a maneuvering member (3), characterized in that said maneuvering member (3) can rotate relative to the base while being connected to said wedge (2), which bears a push-piece (21) forming a lever designed to come into bearing contact against said ramp to modify the vertical position of the support element (3) by pivoting.