The seat back frame of a vehicle seat has been formed out of a sheet iron blank into a pressed piece of sheet iron. The seat back frame is provided with a main region and with a border oriented transversely to said main region. The border being composed of merging portions, viz., of a top border, a left and a right bent corner border and a left and a right lateral border. A left and a right stiffening bead is provided, each of which being located both in an upper end region of the corresponding lateral border and in a portion of the main region a) that is directly adjacent said upper end region and that is b) in the neighborhood of the corresponding corner border.