This invention provides a supporting structure of a headrest bracket comprising attaching portions (flat-like areas in the frontal view) provided on the upper frame of the vehicle seat, with attaching wall portions formed on both ends of each flat-like attaching portion, whereby one side of the headrest bracket is put onto the attaching portion, so that welding points made between the free ends of the attaching wall and on the sides of the headrest bracket are provided, and the free ends are welded, and the welding point made between the upper and/or lower ends of the attaching portion and on the sides of the headrest bracket is horizontally welded.