The present invention provides a process for producing silicon carbide fibers having a C/Si molar ratio of from 0.85 to 1.39 and excellent in heat resistance and strength at high temperatures, while conventional processes have not been able to produce the fibers having the ratio of less than 1.56.
The process of the present invention comprises the steps of rendering infusible precursory fibers made from an organosilicon polymer compound to obtain infusible fibers, then primarily baking the infusible fibers in a hydrogen gas-containing atmosphere while raising the temperature thereof to obtain primarily baked fibers, and further secondarily baking the primarily baked fibers to obtain final fibers. The secondary baking is performed in the atmosphere of a mixed gas of an inert gas with hydrogen chloride gas at 1,500 to 2,200 °C.