Silicon carbide (SiC) and diamond were decomposed to CO2(g) by the photocatalysis with TiO2 at room temperature, although the decomposition rate of diamond was very slow. According to the XPS spectra of Si2p on the SiC surface, SiO2 was simultaneously formed on the surface by the TiO2 photocatalysis. The thickness of the SiO2 formed on the SiC surface during the photocatalytic oxidation for 1 h was estimated to be about 40 Angstrom from the depth profile of the XPS spectra using At etching. The SiC surface was oxidized by the TiO2 photocatalysis even under the condition without a direct contact with the TiO2. This indicates that the photocatalytic oxidation of the SiC occurs due to active oxygen species photogenerated on the TiO2 surface, but not by hole produced in the valence band of the TiO2. Moreover, a remote surface treatment system using the quartz beads coated with TiO2 was developed for the SiC surface oxidation. Consequently, the TiO2 photocatalysis will be very useful for the surface treatment of SiC such as photopatterning without defects and damage to the substrate because the photocatalytic reaction is carried out under mild conditions.