It is the purpose of this invention to present a process for producing carbon nanostructure in which the mechanism of continuous carbon nanostructure growth can be optimized and a high-quality carbon nanostructure can be produced, a catalyst for carbon nanostructure growth which is for use in the production, a raw-material gas and a carrier gas for producing the same, and an apparatus for producing the same. The process for carbon nanostructure production, in which the length of the nanostructure can be continuously controlled comprises feeding a carrier gas and a raw-material gas to a reaction chamber (4) to produce a carbon nanostructure (2) with a catalytic structure (6), wherein the concentrations of oxidation gases contained in the carrier gas and raw-material gas, such as oxygen and water (in the case of raw-material acetylene gas, minor ingredients such as DMF and acetone, which are solvents), are regulated to a moderate value. Thus, a carbon nanostructure of good quality can be produced at a high efficiency.