NOVELTY - A hydrogen producing apparatus has Bunsen reactor (2), a hydrogen iodide concentration decomposition device (A), a sulfuric acid concentration decomposition device (B), an electrodialyzer (32) and an upstream-side distilling column (30). The reactor generates sulfuric acid aqueous solution and hydrogen iodide aqueous solution from iodine, sulfur dioxide and water. The distilling column, which concentrates hydrogen iodide aqueous solution before flowing into electrodialyzer by distillation, is provided in the upstream side of electrodialyzer.    USE - For producing hydrogen (claimed).    ADVANTAGE - The hydrogen production apparatus is economical and has improved hydrogen production efficiency.    DETAILED DESCRIPTION - A hydrogen producing apparatus has Bunsen reactor (2), a hydrogen iodide concentration decomposition device (A), a sulfuric acid concentration decomposition device (B), an electrodialyzer (32) and an upstream-side distilling column (30). The reactor generates sulfuric acid aqueous solution and hydrogen iodide aqueous solution from iodine, sulfur dioxide and water. The device (A) decomposes hydrogen iodide after concentrating hydrogen iodide aqueous solution, obtains hydrogen as byproduct, and supplies iodine to the reactor. The device (B) decomposes sulfuric acid after concentrating sulfuric acid aqueous solution, obtains oxygen, and supplies sulfur dioxide to the reactor. The electrodialyzer concentrates hydrogen iodide aqueous solution exceeding azeotropy concentration of hydrogen iodide aqueous solution provided in the device (A). The distilling column, which concentrates hydrogen iodide aqueous solution before flowing into electrodialyzer by distillation, is provided in the upstream side of electrodialyzer.    DESCRIPTION OF DRAWING(S) - The figure shows the block diagram of iodination hydrogen purification concentrator. (Drawing includes non-English language text)    Bunsen reactor (2)    Iodination hydrogen purification concentrator (9)    Iodination hydrocracking device (11)    Distilling column (30)    Electrodialyzer (32)