To provide a new roofing structure without requiring the work for cutting a waterproof connecting material at a corner ridge part or the like.

In this roofing structure that the waterproof connecting material 2 is provided in a back side of the butt part of the both side ends of a right and a left adjacent flat tiles 1 to roof the flat tiles 1, as the flat tile to be positioned at a right and a left ends, the adjustable tile 4 having a width dimension X satisfying the condition that a+b/2≤X≤L-(a+b/2) is used. L means a width dimension of the flat tile, (a) means a projecting width dimension of the flat tile, and b means a width dimension of the waterproof connecting material.