A flexible display device includes a display panel that includes a bending area that is bendable about a bending axis that extends in a first direction and first and second non-bending areas spaced apart from each other in a second direction that intersects the first direction with the bending area interposed therebetween, and a support member under the display panel. The support member includes a first member that overlaps the bending area and that includes a first metal and a first bonding metal with different melting points, and a bonding member in contact with one side of the first member and that extends in the first direction. The bonding member includes the same metal as the first bonding metal. A concentration of the first bonding metal in the first member progressively decreases from the one side toward the bending axis.