A method of producing a carbon nanotube film structure having a substrate and a carbon nanotube layer, comprises a placing step of placing a carbon nanotube film comprising a plurality of carbon nanotubes aligned in one direction within a film plane on the substrate; and a densifying step of applying a densifying treatment to the carbon nanotube film thereby forming the carbon nanotube layer having the weight density of the carbon nanotube to 0.1 g/cm3 or more. Thus, a problem of island-like shrinkage caused while a highly densified CNT layer is being manufactured is solved, and a high-quality CNT film structure wherein the aligned CNT layer having a high density and uniform thickness is deposited on the substrate.