Bioluminescence reaction by bacterial luciferase has been successfully controlled by a controlled-potential electrolysis using platinum-mesh electrode to regenerate the reduced form of flavin mononucleotide (FMNH2), which is one of the substrates of the reaction. It was found that the regeneration of FMNH2 is facilitated by the adsorbed hydrogen atoms formed on a platinum electrode surface in the presence of phosphate ions.