A flexible display device includes: a flexible display module; a first support member below the flexible display module, the first support member including a plurality of first blocks that are arranged adjacent to each other in a first direction; and a second support member including a plurality of second blocks that are arranged to correspond to the plurality of first blocks and arranged adjacent to each other in the first direction, and each of the plurality of second blocks overlaps a corresponding first block of the plurality of first blocks in a first configuration, and the second support member is movable in the first direction between a second configuration, in which a second block of the plurality of second blocks overlaps two adjacent first blocks of the plurality of first blocks, and the first configuration.