A flexible display device comprising: a display panel layer comprising: a display area comprising a plurality of light emitting areas (PXA-R, PXA-G, PXA-B) and a non-light emitting area (NPXA) adjacent to the plurality of light emitting areas (PXA-R, PXA-G, PXA-B); and a non-display area adjacent to the display area, the display panel layer forming a first display panel surface (BS1-L) and a second display panel surface (BS1-U) facing the first display panel surface (BS1-L) in a thickness direction; a touch sensing layer forming a first base surface; a reflection prevention layer forming a second base surface; and a window layer forming an outer surface (OS-U), wherein: the touch sensing layer is disposed directly on one of the first display panel surface (BS1-L), and the second display panel surface (BS1-U); the reflection prevention layer is disposed directly on the second display panel surface (BS1-U) or the first base surface; the window layer is disposed directly on the second base surface; and the window layer comprises a window protection layer disposed directly on the second base surface characterized in that in the display area, the first base surface and a surface of the window protection layer are separated by a first distance in the thickness direction; in the non-display area, the first base surface and the surface of the window protection layer (WBS, WBS', WBS") are separated by a second distance in the thickness direction, the second distance being greater than the first distance; and the surface of the window protection layer is completely spaced apart from the first base surface. a display panel layer comprising: a display area comprising a plurality of light emitting areas (PXA-R, PXA-G, PXA-B) and a non-light emitting area (NPXA) adjacent to the plurality of light emitting areas (PXA-R, PXA-G, PXA-B); and a non-display area adjacent to the display area, the display panel layer forming a first display panel surface (BS1-L) and a second display panel surface (BS1-U) facing the first display panel surface (BS1-L) in a thickness direction; a display area comprising a plurality of light emitting areas (PXA-R, PXA-G, PXA-B) and a non-light emitting area (NPXA) adjacent to the plurality of light emitting areas (PXA-R, PXA-G, PXA-B); and a non-display area adjacent to the display area, the display panel layer forming a first display panel surface (BS1-L) and a second display panel surface (BS1-U) facing the first display panel surface (BS1-L) in a thickness direction; a touch sensing layer forming a first base surface; a reflection prevention layer forming a second base surface; and a window layer forming an outer surface (OS-U), wherein: the touch sensing layer is disposed directly on one of the first display panel surface (BS1-L), and the second display panel surface (BS1-U); the reflection prevention layer is disposed directly on the second display panel surface (BS1-U) or the first base surface; the window layer is disposed directly on the second base surface; and the window layer comprises a window protection layer disposed directly on the second base surface the touch sensing layer is disposed directly on one of the first display panel surface (BS1-L), and the second display panel surface (BS1-U); the reflection prevention layer is disposed directly on the second display panel surface (BS1-U) or the first base surface; the window layer is disposed directly on the second base surface; and the window layer comprises a window protection layer disposed directly on the second base surface characterized in that in the display area, the first base surface and a surface of the window protection layer are separated by a first distance in the thickness direction; in the non-display area, the first base surface and the surface of the window protection layer (WBS, WBS', WBS") are separated by a second distance in the thickness direction, the second distance being greater than the first distance; and the surface of the window protection layer is completely spaced apart from the first base surface. in the display area, the first base surface and a surface of the window protection layer are separated by a first distance in the thickness direction; in the non-display area, the first base surface and the surface of the window protection layer (WBS, WBS', WBS") are separated by a second distance in the thickness direction, the second distance being greater than the first distance; and the surface of the window protection layer is completely spaced apart from the first base surface.