The photoresponses on the desorption of atomic hydrogen (H) from a titanium dioxide (TiO2) surface, induced by the tip of a scanning tunneling microscope, were investigated under irradiation of the surface with ultraviolet (UV) photons. On UV irradiation, an increase in the reaction yield of H desorption from the TiO2 surface was observed. The mechanism of the increase in the H desorption yield observed under UV irradiation is discussed.