A shadow mask frame assembly of a flat cathode ray tube (CRT) includes a shadow mask including a plurality of strips formed at a main body in a vertical direction by being separated a predetermined distance by slits and a plurality of bridges forming slots by connecting neighboring strips and sectioning the slits, in which the slots include a first slot group including slots having a wide interval between the bridges and a second slot group including slots having a narrow interval between the bridges, first and second support members secured at a long side portion of the shadow mask, and a frame including first and second elastic members, either end portion of each of which is secured to each of the first and second support members, for applying a tension force to the shadow mask.