Abstract: The invention relates to an apparatus for bending structural metal rails, preferably rails for multi-glazed windows, and gives instructions for a bending unit (20) having two wringing heads (6) which can be displaced relative to the width of the rail, for in an open position to allow the infeed of rails (5) having various width, and in an attracted position to clamp a portion of the rail (5) for the bending thereof by turning the wringing heads (6).