NOVELTY - The system has a laminated portion that comprises a photovoltaic layer (41) which performs charge separation with light energy. The electrolyte solution tank accommodates two electrolyte solutions respectively immersing oxidation electrode layer and reduction electrode layer. A carbon dioxide reduction unit comprises an ion transfer path to which ion is moved between two electrolyte solutions. The carbon dioxide supply portion comprises a gas supplying pipeline for supplying gas containing carbon dioxide generated by carbon dioxide generation unit to second electrolyte solution.    USE - Photoelectrochemical-reaction system for use with iron foundry, chemical plant and refuse-disposal field.    ADVANTAGE - Improved energy efficiency is ensured, and the electromotive force generated in the photovoltaic layer is utilized more effectively.    DETAILED DESCRIPTION - The gas supplying pipeline is comprised with a gas supply hole which is configured to discharge the gas containing carbon dioxide introduced from the carbon dioxide generation unit while immersing in second electrolyte solution. The carbon dioxide supply unit is configured to supply the gas second electrolyte solution by the discharge pressure of the gas containing the carbon dioxide emitted from the carbon dioxide generation unit. The laminated portion is provided with the oxidation-catalyst layer provided on the oxidation electrode layer, and the reduction catalyst layer provided on the reduction electrode layer. The carbon dioxide generation reduction unit is configured to reduce the carbon dioxide, generate carbon compound, oxidize water and generates oxygen and hydrogen ion. A product collection unit is configured to collect the carbon compound generated in the carbon dioxide reduction unit. A carbon dioxide separation unit is configured to separate carbon dioxide from the carbon compound generated in the carbon dioxide reduction unit. An impurity removal unit is configured to remove impurity from the gas containing the carbon dioxide emitted from the carbon dioxide generation unit. The carbon dioxide supply unit is configured to supply the gas by which the impurity is removed. A carbon dioxide absorption unit is configured to absorb the gas by which the impurity is removed in the impurity removal portion, and the carbon dioxide separated from the carbon compound in the carbon dioxide separation unit. The carbon dioxide restoration unit is configured to restore water and generate carbon compound and the mixture of hydrogen. A product collection unit is configured to collect the carbon compound generated in the carbon dioxide reduction unit.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of the photoelectrochemical-reaction system.    Photoelectric chemical module (1)    Tubular electrolyte solution tank (2)    Tubular photovoltaic cell (3)    Catalyst layer (22)    Photovoltaic layer (41)