Among imaging techniques, fluorescence microscopy is a unique method to noninvasively image individual molecules in whole cells. If the three-dimensional spatial precision is improved to the angstrom level, various molecular arrangements in the cell can be visualized on an individual basis. We have developed a cryogenic-reflecting microscope with a numerical aperture of 0.99 and an imaging stability of 0.05 nm in standard deviation at a temperature of 1.8 K. The key optics to realize the cryogenic performances is the reflecting objective developed by our laboratory. With this cryogenic microscope, an individual fluorescent molecule (ATTO647N) at 1.8 K was localized with standard errors of 0.53 nm (x), 0.31 nm (y), and 0.90 nm (z) when 10(6) fluorescence photons from the molecule were accumulated in 5 min.