To solve the problems of the degradation of product quality, the occurrence of a great deal of product failures and the like due to the large deformation of overlap parts in baking, because the overlap is in a cantilever state to a tile body and lifted from a setter when baked in a flat baking method in which roof tiles are placed flat on a setter and baked in a baking process out of a manufacturing process, regarding the roof tiles made of clay roof tiles.

Baking is performed with an underlap rear surface (7) and an overlap rear surface (5) of the roof tile (1) being simultaneously grounded on a setter surface (12) when the roof tile is placed on the setter (11). A roof tile body rear surface (6) is provided with one or more protrusions (9) to bake the roof tile more stably, or the underlap rear surface and the overlap rear surface are provided with protrusions (10, 8) so that the overlap rear surface can be easily grounded on the setter surface. Further, the quantity of protrusions is changed according to the width of the roof tile to adjust behavior in a length direction and provide strength to a load from the surface side of the roof tile body (3).