The present invention relates to a flexible display device, comprising: a first body; a second body configured to be movable relative to the first body; a support plate installed on the rear surface of the second body and configured to be movable relative to the second body; a flexible display unit configured such that areas exposed to the outside are changed while the first body and the second body move relative to each other; and a driving unit generating a driving force such that the second body slides with respect to the first body, wherein as the driving unit causes a movement of the second body through a rotational force by means of a motor, the areas exposed to the outside of the front part and the rear part of the flexible display unit can be changed respectively.