A rail of a flat type cathode ray tube is disclosed, wherein the flat type cathode ray tube comprises a panel having a deposited fluorescent surface therein and of which interior and exterior surfaces are substantially flat, a funnel connected to the panel; a shadow mask arranged with the inner surface of the panel with a predetermined gap, and a rail fixed to the panel and combined with the shadow mask. In the flat type cathode ray tube, if a height of the rail is L, the rail maintains a predetermined gap of 0.1L˜0.3L with the panel and is fixed by a frit glass.