A semiconductor device uses a carbon nanotube structure, which reduces an electric resistance and a thermal resistance by increasing a density of the carbon nanotubes. An insulation film covers a first electrically conductive material. A second electrically conductive material is provided on the insulation film. A plurality of carbon nanotubes extend through the insulation film by being filled in an opening part that exposes the first electrically conductive material. The carbon nanotubes electrically connect the first electrically conductive material and the second electrically conductive material to each other. Ends of the carbon nanotubes are fixed to a recessed part provided on a surface of the first electrically conductive material.