The dose distribution and the spectrum variation of neutrons due to the skyshine effect have been measured with various detectors in the environment surrounding the electron synchrotron of the Institute for Nuclear Study, University of Tokyo. The dose distribution and the spectra of neutrons on the outer surface of the concrete shield of the synchrotron building were also measured in order to get information on the skyshine source. The measured neutron spectra both at the source and in the environment show an approximate 1/E spectrum below ∼100 keV, but the latter is much softer than the former above that energy. These experimental data were analyzed with the multigroup Monte Carlo code, MMCR, with the result that the calculated results are in good agreement with the experiment. This experiment is uniquely worthwhile since the skyshine of the radiation directed almost vertically into the air from the accelerator building was measured and the energy spectrum and dose distributions of the neutron source were clarified.