NOVELTY - The apparatus has electrodialysis tank (10) that generates nitric acid and sodium hydroxide. A dissolution tank (32) dissolves to-be-dissolved substance containing group 2 element in nitric acid to form nitrate solution of group 2 element. A gas-absorpion tower (34) absorbs sodium hydroxide and carbon dioxide to generate sodium carbonate solution of group 2 element. A reaction tank (36) receives nitrate solution and sodium carbonate solution to generate carbonate of group 2 element. A chamber (30) receives sodium nitrate solution circulated through reaction tank.    USE - Apparatus for fixing carbon-dioxide in atmosphere.    ADVANTAGE - Since the alkali source is taken from rock and waste material for circulating through reaction tank of carbon-dioxide fixation apparatus, the cost of the carbon-dioxide fixation apparatus is reduced. The fixation of carbon dioxide can be performed directly through circulation of acid and alkali in the reaction tank. The generation of carbon-dioxide is reduced by the carbon-dioxide fixation apparatus, as the fixation apparatus uses solar cell as direct current power supply.    DETAILED DESCRIPTION - Three bipolar membranes (16,17,22), anion exchange membrane (18), and cation exchange membrane (20) are arranged between positive electrode (12) and negative electrode (14) of electrodialysis tank of carbon-dioxide fixation apparatus. The electric power is supplied to the electrodialysis tank by direct current power supply (24), such that the amount of input energies per amount of fixation of 1 mol of carbon dioxide is 300-500 kJ.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic block diagram of carbon-dioxide fixation apparatus. (Drawing includes non-English language text)    Electrodialysis tank (10)    Positive electrode (12)    Negative electrode (14)    Bipolar membranes (16,17,22)    Anion exchange membrane (18)    Cation exchange membrane (20)    Direct current power supply (24)    Salt solution acceptance chamber (30)    Dissolution tank (32)    Gas-absorpion tower (34)    Reaction tank (36)