NOVELTY - Sulfur dioxide is adsorbed using an adsorption solution in sulfur dioxide absorption tower, and oxygen is discharged outside the reactor. The sulfur dioxide is attached and detached from adsorption solution. The attached and detached sulfur dioxide is transferred to sulfur dioxide absorptive tower. The sulfuric acid solution in which sulfur dioxide is dissolved, is transferred to electrolysis device to obtain hydrogen and sulfuric acid. The sulfur dioxide and oxygen are circulated to sulfur dioxide absorption tower such that the sulfur dioxide is separated from oxygen.    USE - Production of hydrogen.    ADVANTAGE - The method enables production of hydrogen, with reduced energy consumption.    DETAILED DESCRIPTION - Sulfur dioxide is adsorbed using an adsorption solution in sulfur dioxide absorption tower, and oxygen is discharged outside the reactor. The sulfur dioxide is attached and detached from adsorption solution in which sulfur dioxide is absorbed. The attached and detached sulfur dioxide is transferred to sulfur dioxide absorptive tower, and adsorption solution is circulated to sulfur dioxide absorption tower. The sulfuric acid solution in which sulfur dioxide is dissolved, is transferred to electrolysis device from sulfur dioxide absorptive tower to obtain hydrogen and sulfuric acid. The sulfuric acid and sulfuric acid solution flowing out from vapor-liquid separation apparatus are mixed, after injecting to decompressor of sulfuric acid multi-stage distillation column (I) and multi-stage distillation column (II), and sulfuric acid solution is concentrated. The concentrated sulfuric acid is passed through sulfuric acid evaporator, sulfuric acid disassembler, sulfur trioxide disassembler and heat exchanger successively to obtain condensed sulfuric acid solution, sulfur dioxide and oxygen. The condensed sulfuric acid solution, sulfur dioxide and oxygen are separated to liquid and air comprising sulfur dioxide and oxygen. The sulfur dioxide and oxygen are circulated to sulfur dioxide absorption tower such that the sulfur dioxide is separated from oxygen, and liquid sulfuric acid solution is circulated to the sulfuric acid multi-stage distillation column (S1). An INDEPENDENT CLAIM is included for device for producing hydrogen.