To provide a system for recovering hydrogen energy which gasifies an organic substance in sludge 2 such as sewage sludge discharged from a general home, sludge discharged from a plant, brackish sludge of a river, dredging sludge of a sea, seaside sludge and sludge to make an energy gas such as hydrogen gas 15 or carbon monooxide gas 16, and enhances reduction of a load having an influence on environment by carrying out stabilization treatment of an inorganic substance; and a method for recovering the hydrogen energy.

The system for recovering the hydrogen energy comprises gasifying means 3 for making the hydrogen gas 15 or the carbon monooxide gas 16 of the organic substance in the sludge 2 such as the sewage sludge discharged from the general home, the sludge discharged from the plant, the brackish sludge of the river, the dredging sludge of the sea, the seaside sludge and the sludge, and melting means 4 for melting the inorganic substance at high temperature to finally make harmless as a high-temperature liquid substance 9.