A flexible display device is configured to be bendable along at least one bending axis, have two opposite sides at both ends of the bending axis, respectively, and include a first substrate and a second substrate opposite to each other, and a hetero-shaped double-sided adhesive tape bonding the first substrate and the second substrate to each other on at least one of the two opposite sides. The hetero-shaped double-sided adhesive tape includes a lower adhesive layer, a base material layer, and an upper adhesive layer which are stacked together in sequence. In a stacking direction of the lower adhesive layer, the base material layer and the upper adhesive layer, the upper adhesive layer has a non-overlapping region that does not overlap the lower adhesive layer, and/or the lower adhesive layer has a non-overlapping region that does not overlap the upper adhesive layer.