Abstract: Window lifter for vehicle door, comprising two rails which are mutually parallel and parallel to the travel of the window glass (3), a rider mounted so that it can slide on each rail and secured to a window glass support clamp device (14) including a part (15) fixed to the rider and a part (16) which can move, articulated to the fixed part, as well as a system of cables which are connected to the riders and provided with means for driving the said cables and the riders; the mobile part (16) of each clamp has a bearing surface (23) for the window glass, situated substantially along the axis of sliding of the rider, this surface being formed by a bent end (24) extending a lateral lug (25) of the mobile part (16). This arrangement makes it possible for the weight of the window glass (3) to be borne on a bearing surface situated on the axis of sliding of the rider along the rail, which eliminates any cantilever effect and therefore any parasitic forces in the mechanism during travel of the window glass.