Silicon carbide nanowires (SiCNWs) (with diameters of tens of nanometer and aspect ratio well above 103), consisting of β-SiC one-dimensional single crystals wrapped in amorphous nitrogen-containing SiO2 sheaths, were efficiently synthesized in gram quantities by autogenous combustion synthesis using Si as a defluorination reagent of poly(tetrafluoroethylene). The combustion temperature was evaluated using the emission spectroscopy. Vapor–liquid–solid mechanism of a self-catalytic growth of the SiCNWs is proposed.