This paper describes the formation of fluoride layer on the surface of hydriding alloys. The fluoride formation reaction consists of a reduction removal process of surface oxide and a fluorination process. Specific surface area of alloy grains can be increased by the hydrogenation reaction in the surface layer accompanied with the removal of surface oxide, which results in easier permeation of molecular hydrogen into fluoride layer. During the fluorination process, a large amount of Ni in the alloy components is eluted, which results in the reduction of Ni distribution immediately under the fluoride layer in the alloy. Consequently, collector sites near the surface are reduced, and conductivity among alloy grains is degraded. To enhance the hydrogen collector sites, specific surface area of alloy grains can be increased by controlling the pH value of fluorination treatment solution in a given range. Moreover, performance of fluoride layer can be advanced by electrochemically dispersing metal Ni in the fluoride layer using Ni complex ion mixed in the treatment solution. 2 refs., 3 figs.