Included are a nano-carbon material production unit for producing a nano-carbon material using a fluidized catalyst formed by granulating a carrier supporting an active component, an acid treatment unit for dissolving and separating a catalyst by an acid solution by feeding a catalyst-containing nano-carbon material into the acid solution, and a pH adjustment unit, which is an anti-agglomeration treatment unit, provided on a downstream side of the acid treatment unit, for performing an anti-agglomeration treatment to prevent agglomeration among nano-carbons due to repulsion caused by dissociation among oxygen-containing functional groups added to the nano-carbon material.