A foldable display device includes a flexible display panel including a bendable area; and a first supporter including a first multi-joint member, a complex support unit, and a second multi-joint member consecutively arranged in a first direction, and supporting the bendable area, and the complex support unit includes: a flat support unit combined to the first multi-joint member and the second multi-joint member in a rotatable manner with respect to a combination axis in parallel to a second direction crossing the first direction; and a curved support unit neighboring the flat support unit in the second direction and combined to the first multi-joint member and the second multi-joint member such that a rising height of the curved support unit changes in a third direction according to a rotation state of the flat support unit relative to the first multi-joint member and the second multi-joint member.