To provide a support structure of rib glass capable of restraining a deflection quantity of surface glass within an allowable range.

In the support composition of the rib glass, an inside receiving block 45 is formed as an L-shaped cross-sectional member formed of one edge 45a running along a wall surface 35a of an inside lower rib glass inserting groove 34, and the other edge 45b running along a bottom surface 35b of the inside lower rib glass inserting groove 34. According to the support composition of the rib glass, inside rib glass 14 is installed at a right angle to the surface glass 12, the upper end 14a of this inside rib glass 14 is inserted into the inside lower rib glass inserting groove 34 of a support member 21, and the one edge 45a of the inside receiving block 45 is interposed between the wall surface 35a of the inside lower rib glass inserting groove 34 and the upper end 14a of the inside rib glass 14 to prevent a horizontal movement of the inside rib glass 14.