A display device includes a first display unit and a second display unit disposed parallel with the first display unit in a first position or a second position, wherein the first display unit and the second display unit overlap in the first position and are extended out in the second position. The display device further includes a sliding unit having at least one engaging groove which the first display unit and the second display unit are inserted into and slide through, a first driving unit disposed on one side of the first display unit, and a second driving unit disposed on one side of the second display unit.