In this paper the author shows the details of several problems related to the average sky factor of unit block in an urban space. These problems are as follows. (1) The relation between the average sky factor and the site area, or the road ratio. (2) The comparative study of the max- imum of average sky factor at an unit block and the average sky factor at the same block of which the-building coverage ratio is 100%. (3) The regression equation for the average sky factor, or the building coverage ratio in which the occupied sky factor has a maximum.
