The CO2 fixation system, that is formic acid production from CO2 with FDH from Saccharomyces cerevisiae and reduced Methyl viologen produced by the visible light photosensitization of zinc tetrakis( 4-methylpyridyl) porphyrin, was investigated. When the sample solution containing triethanolamine, zinc tetrakis(4-methylpyridyl) porphyrin, Methyl viologen, NaHCO3 and FDH in phosphate buffer was irradiated, formic acid was produced. The amount of formic acid production and the yield of CO2 to formic acid were estimated to be 0.104 +/- 0.008 mM and 10.4%, respectively.