The reaction process on allophane-dispersing titania electrodes of photofuel cells was investigated in electrolytes containing glucose as the fuel material at different concentrations. A low allophane amount improved the glucose adsorption-degradation relay on the electrodes. The dispersion process of the glucose molecules adsorbed on the allophane to the titania was the rate-determining step in the present systems. The reaction rate decreased when high amounts of intermediate products were adsorbed on the allophane and titania surface.