A flexible display device is disclosed. The flexible display device includes a flexible display panel and a back cover disposed on a back surface of the flexible display panel and having a plurality of opening patterns provided in the third region. The plurality of opening patterns include opening patterns arranged in odd-numbered columns along the first direction and opening patterns arranged in even-numbered columns along the first direction. Each of the opening patterns includes a first portion having a width becoming smaller in a second direction intersecting with the first direction as the first portion progresses along the first direction and a second portion extending from the first portion and having a width becoming greater in the second direction as the second portion progresses along the first direction.