A method of manufacturing a semiconductor device having an interconnection part formed of multiple carbon nanotubes is disclosed. The method includes the steps of (a) forming a growth mode control layer controlling the growth mode of the carbon nanotubes, (b) forming a catalyst layer on the growth mode control layer, and (c) causing the carbon nanotubes to grow by heating the catalyst layer by thermal CVD so that the carbon nanotubes serve as the interconnection part. The growth mode control layer is formed by sputtering or vacuum deposition in an atmospheric gas, using a metal selected from a group of Ti, Mo, V, Nb, and W. The growth mode is controlled in accordance with a predetermined concentration of oxygen gas of the atmospheric gas.