The topography of the rutile TiO2(110) surface was observed with a noncontact atomic force microscope (NC-AFTA) in an atmospheric pressure of N-2. Oxygen-atom rows arrayed with an interval of 0.65 nm and individual oxygen-atom vacancies in the rows were resolved in constant frequency-shift topography, though the cantilever oscillation was damped by the viscous resistance of the dense ambient N-2 gas.