A method of manufacturing a flexible display device includes forming a base substrate on a first sacrificial layer formed on a first supporting substrate, forming a display device array on the base substrate, forming a second sacrificial layer on a second supporting substrate, forming a touch array on the second sacrificial layer, adhering the first supporting substrate onto the second supporting substrate using an adhesive, irradiating laser energy onto the first sacrificial layer to remove the first sacrificial layer and separate the first supporting substrate from the base substrate, and irradiating laser energy onto the second sacrificial layer to separate interfaces of the second supporting substrate and the second sacrificial layer from each other, such that the second sacrificial layer is fixed on the touch array, The second sacrificial layer includes at least one of oxidized molybdenum, lead zirconate titanate, gallium nitride, and an amorphous silicon based inorganic material.