An array substrate for a flexible display device, the array substrate including a mother substrate, a plurality of display units separated on the mother substrate, in which the plurality of display units include display regions that display images and non-display regions that extend from the display regions to edges of each of the plurality of display units, respectively, encapsulation units covering the display regions of the plurality of display units, respectively, a plurality of testing wires in a wire region between adjacent display units from among the plurality of display units, in which the plurality of testing wires are electrically connected to each of the plurality of display units, and crack preventing units in the non-display regions between edges of the encapsulation units and the edges of each of the plurality of display units, respectively.