To provide a manufacturing device for sunlight concentrating high temperature furnace gas which can form a high temperature furnace of practical size of 1,000°C class by enabling concentration of sunlight in an extensive area, and in which water and sulfuric acid are thermally decomposed, and sunlight energy is utilized with high efficiency because of high temperature.

By converting the sunlight into a laser beam and putting it together, hydrogen can be generated. Since sunlight-excited laser beam can be transported over longer distance than a normal sunlight due to coherent characteristics, the sunlight in the extensive area of 1-10 km around can be collected efficiently. As a result, the temperature of the high temperature furnace reaches 1,000°C or more, so that hydrogen generation by sulfuric acid/iodine cycle and hydrogen generation by direct thermal decomposition of steam are enabled.