Abstract: To provide a CO2 recycling device which is compact and with which electricity consumption can be reduced. The invention is a device for manufacturing multilayer carbon nanotubes, carbon onions or nano-carbons, using a microwave plasma CVD method, taking the CO2 gas within a carbon monoxide-containing gas as the carbon source. The device comprises a microwave oscillator, a microwave waveguide and a reaction tube provided within the microwave waveguide, and a gas inlet pipe and an exhaust pipe are configured from the reaction tube which returns within the microwave waveguide and a ceramic-type heater provided on the inner wall of the gas inlet pipe. Then, microwave plasma is generated at the position where the reaction tube returns, and the multilayer carbon nanotube, carbon onion or nano-carbon formed is adhered to the inner wall of the exhaust pipe.