Provided is a carbon nanotube field effect transistor manufacturing method wherein carbon nanotube field effect transistors having excellent stable electric conduction property are manufactured with excellent reproducibility. After arranging carbon nanotubes to be a channel on a substrate, the carbon nanotubes are covered with an insulating protection film. Then, a source electrode and a drain electrode are formed on the insulating protection film. At this time, a contact hole is formed on the protection film, and the carbon nanotubes are connected with the source electrode and the drain electrode. Then, a wiring protection film, a conductive film and a plasma CVD film are sequentially formed on the insulating protection film, the source electrode and the drain electrode. In the field effect transistor thus manufactured, since the carbon nanotubes to be the channel are not contaminated and not damaged, excellent stable electric conductive property is exhibited.