PURPOSE: To facilitate the formation of a curved surface by securing a U-like cross-sectional shape attaching frame which includes two side pieces having different heights and which is opened outward, to a peripheral edge of a glass block.

CONSTITUTION: A bottom piece 4 of a U-like cross-sectional shape attaching frame 3 opened over its overall length is joined to the outer peripheral part of a glass block 1 by means of an adhesive 5. Then, the height h1 of a side piece 2a of the attaching frame 3 is set to be larger than the height h2 of a side piece 2b thereof. Further, the heights of the side pieces 2 attached to the upper and lower parts of the block 1 are set to be equal to each other. Then, a plurality of the blocks 1 are stacked one upon another with the side pieces 2a being superposed with each other between the blocks 1. Then, they are joined and fixed together by inserting screws 7 in elongated holes 6, and decorative joints 9 are formed in joint parts 8 at the convex side of a wall A. With this arrangement, it is possible to facilitate the formation of a curved surface.