A photoelectrode composed of Zn-porphyrin dye and semiconductor titania nanosheets (TNS, TiO89O2) where Zn-porphyrin was densely adsorbed without aggregation was fabricated. Efficient electron injection from excited Zn-porphyrin to TNS was observed under the irradiation of visible light. The absorbed photon to current conversion efficiency (APCE) was estimated to be 31%. Action spectra for the current coincided well with the absorption spectrum of Zn-porphyrin. These results indicate that TNS could act as an efficient n-type semiconductor.