Fireworks displays in metropolitan area are typical features in Japanese summer. When we enjoy fireworks displays, we should take into account the existence of surrounding buildings, shielding visibility of fireworks. In this study, we think about the visibility of fireworks in the area which has a lot of buildings and evaluate quantitatively the amount of fireworks caught in the field of vision, considering the shielding by buildings and the view-points of fireworks. In the figure, we calculated the "Solid Angle" of real fireworks displays. It is an indicator of the amount of fireworks caught in the field of vision, that is, how large is fireworks that a spectator is enjoying. This technique can be also applied to various practical field, such as disaster prevention.