Solar spectra in the wavelength region 427-451nm were observed by a spectrophotometer on board a balloon flown at Sanriku Balloon Center (39.2°N, 141.8°E) from noon to sunset on May 29, 1978. The NO2 slant column density along the solar ray path was calculated by a statistical analysis to find the very weak absorption structure of NO2 in the solar spectra, referring to that obtained at a solar zenith angle of 35° and at a balloon altitude of 24km. A vertical distribution of NO2 in the 14-35km altitude region was obtained from the apparent variation of the slant column density with solar zenith angle. The NO2 profile obtained in this study is close to those obtained with the visible absorption method in Canada. The peak density was around 5×109 molecules•cm-3 at 22-25km, and the vertical column density, 7×1015 molecules•cm-2.