NOVELTY - A reducing and fixing system (1) of carbon dioxide has a reaction portion (1A) having an electrolyte (13) between cathode (11) and anode (12). An electron is produced by oxidation reaction in anode, and carbon dioxide of gaseous phase is fixed by reductive reaction in cathode. Cation or anion is conveyed through electrolyte such that bias of electric charge accompanying reaction is compensated. Oxidation reaction is reaction which becomes more negative than onset electric potential of reductive reaction in cathode of operating condition with same onset electric potential of oxidation.    USE - Reducing and fixing system of carbon dioxide used for reducing and fixing carbon dioxide for manufacturing useful carbon resource (claimed) and for polymer electrolyte fuel cell and phosphoric acid fuel cell.    ADVANTAGE - The carbon dioxide is fixed in a gaseous phase without applying external energy.    DETAILED DESCRIPTION - A reducing and fixing system of carbon dioxide has a reaction portion having an electrolyte arranged between cathode and anode. An electron is produced by oxidation reaction in the anode, and carbon dioxide of gaseous phase is fixed by reductive reaction in the cathode. A cation or an anion is conveyed through the electrolyte such that the bias of electric charge between electrodes accompanying the oxidation reaction or the reductive reaction is compensated. An oxidation reaction with anode is reaction which becomes more negative than onset electric potential of reductive reaction of carbon dioxide in the cathode of operating condition with same onset electric potential of the oxidation reaction by an operating temperature. An INDEPENDENT CLAIM is included for manufacture of useful carbon resources, which involves obtaining carbon monoxide using reducing and fixing system.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic view of reducing and fixing system of carbon dioxide.    Reducing and fixing system (1)    Reaction portion (1A)    Cathode (11)    Anode (12)    Electrolyte (13)