A method for manufacturing a nanocarbon material includes the steps of: a) supplying an acetylene-based flammable gas into a torch nozzle at a flow rate such that an ignition at the torch nozzle produces a reducing flame in a cooling zone in a chamber; and b) supplying a cooling medium to a nebulizer disposed upstream of the cooling zone to produce nebulized droplets of the cooling medium such that the nebulized droplets come into contact with the reducing flame in the cooling zone to thereby cause carbon nanoparticles to be entrained in the nebulized droplets.