Methanol synthesis from carbon dioxide has been successfully achieved with the current efficiency of ca．90％ by electrolysis of carbon dioxide-saturated phosphate buffer solution in the presence of formate dehydrogenase and methanol dehydrogenase as electrocatalysts and pyrroloquinoline quinone as an electron relay. The formate dehydrogenase works as an electrocatalyst for reducing carbon dioxide to formate, and the methanol dehydrogenase works in effectively reducing formate to methanol. Using this electrochemical reaction system, photo-induced reduction or carbon dioxide to methanol was devised, where methanol dehydrogenase and pyrroloquinoline quinone were dissolved in zinc sulfide microcrystal colloids in the presence of 2-propanol which worked as a hole scavenger. The quantum efficiency obtained for the phtoproduction of methanol was 5.9％ at irradiation at 280 nm.