NOVELTY - A carbon nano material manufacturing apparatus (2) consists of a cathode (24) immersed in an aqueous medium (W), an anode (22) arranged at intervals at the immersed portion of cathode, a mechanism (48) which introduces an inert gas and forms an inert gas cavity between the cathode and anode, a mechanism (4) which applies voltage between cathode and anode to form an arc discharge generation region (30), and a mechanism (60) in which carbon nano material synthesized from carbon material prepared from arc discharge generation region is collected.    USE - Apparatus is used for manufacturing carbon nano material used of reinforcement materials, friction materials, electroconductivity-control materials, radiation-substance-adsorbing materials used in radioactive-substance adsorption apparatus, radiation-absorbent materials used in radiation absorbers, electromagnetic wave absorbing materials, and gas-adsorption materials (all claimed). Uses include but are not limited to aerospace components, precision machinery components, building materials, sealing materials, heat insulating materials, sports products, sliding materials, ink toner materials, prosthetic arms, artificial legs, artificial skins, health food additives, soil modification material, water purification materials, deodorizing materials, electroconductive sheets, glanding materials, heat radiating components, bio-cell culture cell growth materials, electroconductive channels, organic solar cells, fuel cells, clothing, and catheters.    ADVANTAGE - The apparatus enables efficient, continuous and economical manufacture of carbon nano material.    DETAILED DESCRIPTION - A carbon nano material manufacturing apparatus consists of a cathode in which at least one portion is immersed in an aqueous medium, an anode arranged at intervals at the portion of cathode immersed in aqueous medium in opposing form, a mechanism which introduces an inert gas and forms an inert gas cavity between the cathode and anode, a mechanism which applies a voltage between the cathode and anode to form an arc discharge generation region, and a mechanism in which carbon nano material synthesized from the carbon material prepared from the arc discharge generation region is collected. INDEPENDENT CLAIMS are included for the following:    (1) manufacture of carbon nano material, which involves generating carbon vapors from carbon material formed in the aqueous medium, and recovering the carbon nano material;    (2) radioactive-substance adsorption apparatus provided with a radioactive-substance adsorption unit containing the radioactive-substance adsorbing material; and    (3) radiation absorber provided with a radiation-absorption unit containing the radiation-absorbent material.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the apparatus used of manufacturing carbon nano material.    Carbon nano material manufacturing apparatus (2)    Mechanism which forms arc discharge generation region (4)    Anode (22)    Cathode (24)    Arc discharge generation region (30)    Mechanism which introduces inert gas (48)    Mechanism which collects carbon nano material (60)    Clearance gap (S)    Aqueous medium (W)