To provide, for demand of unrestricted dimensions and design for a support frame for the day-lighting block, a day-lighting block structural body which can be supplied in a short period of time without keeping in stock and is light, while a day-lighting glass block is easy to be constructed and water-proof/water-cutoff performance can be improved by means of the support frame which is excellent in appropriate safety and well-balanced in cost performance.

The day-lighting block structural body is composed of a support frame 21 disposing and supporting a plurality of prism glass 23 in sections formed for day-lighting part 21d and also a joint part 24 located between prism glasses 23 and also between the prism glass 23 and the support frame 21. The support frame 21 is composed in such a way that a metallic frame 21a surrounding the outer periphery of an aligned- and arranged-prism glasses 23, a metallic horizontal plate 21b wherein the day-lighting part 21d is formed at the arrangement section of the prism glasses 23 and a metallic rib plate 21c arranged on the prism glasses 23 in one way and crossed between the facing members of the frame 21a are connected.