To provide a method for improving workability of a corner tile laid on a corner ridge of a roof and safety during execution of work.

A corner tile divided and laid at three points on a corner ridge of a roof is composed of at least a right corner tile and left corner tile each having an underlap at least on its ridge core side and an intermediate corner tile 3 having overlaps 21 on both sides in its width direction. The right corner tile and the left corner tile are locked by tile battens respectively, while the intermediate corner tile 3 is locked to respective underlaps 21 of the right corner tile and the left corner tile. Moreover, in order to improve stability of the execution of work, each of the right corner tile and the left corner tile is provided with a locking surface 27 parallel to the ridge direction of the roof and the intermediate corner tile 3 is provided with a surface 35 to be locked parallel to the ridge direction of the roof, the locking surface and the surface to be locked being locked to each other.