An in-folding type hinge structure having a flexible display panel installed thereon for a mobile communication terminal is provided. In the in-folding type hinge structure, a flexible display panel is provided in two panel portions which are foldably connected to each other, in which folding units can perform a stable folding operation while the two panel portions are being folded or unfolded and the two panel portions are supported such that the panel portions do not rotate over 180 degrees when the two panel portions are fully unfolded, whereby damage of the flexible display panel provided on the surfaces of the two panel portions can be prevented.