It was reported in the previous paper^<2)> that there were significant correlations between the yield of vitamin D_2 in sunlight irradiated ergosterol solutions and the sunlight intensities of both 300〜400 and 300〜330nm ranges. This resultsuggests that the yield can be easily calculated by a simple estimation of sunlight intensity in the indicated range. Therefore, the authors estimated the yearly variation of the sunlight intensity at Kobe and the results are summarized in the following : (1) There was a highly significant correlation between the intensities of 300〜400 and 300〜330nm ranges ; (2) The figures of daily variations of the intensities on fine days showed mountain shapes with a maximum at noon in all seasons, whereas those of bad weather's days showed flat shapes in all seasons because sunlight was cut by cloud ; (3) The intensities of fine days from April to September were significantly higher than those from Nobember to January, whereas these of bad weather's days were extremely lower than those of fine days and there were no significantly differences among months ; (4) The yearly variation from Junein 1973 to May in 1975 was estimated as an average per hour of each month. The result showed that the maximum was the value of either July or August while the minimum was that of December and that the former was about twice as high as the latter.