Heteroepitaxial growth of rutile TiO2 nanorods from SnO2 seeds yielded radial heteromesocrystals consisting of SnO2(head) and rutile TiO2 nanorod(tail) with the SnO2(head) oriented toward the center (TiO2-NR//SnO2 HEMCs). Iron oxide clusters were formed on the surface by the chemisorption-calcination technique. The FeOx-surface modification gives rise to drastic increases in the photocatalytic activity for aerobic oxidation of 2-naphthol under irradiation of UV and visible light. As a 2D-model for 3D-TiO2-NR//SnO2 HEMC, electrochemical measurements were performed for the rutile TiO2-NR array formed on a fluorine-doped tin oxide (SnO2:F) electrode. The results showed that the FeOx clusters possess electrocatalytic activity for a multielectron oxygen reduction reaction, and the high photocurrent of the electrode is remarkably reduced by the FeOx-surface modification. Consequently, the striking photocatalytic activity of FeOx/TiO2-NR//SnO2 HEMCs was ascribable to the switching of the electron transport direction necessary for the charge separation from the long axis of the TiO2 NR to the short axis.