PURPOSE: To reduce an amount of rain flowing down through a gap between tiles and hardly cause the occurrence of leakage of rain by a method wherein a protrusion part is formed on the upper end of the surface of a tile approximately in the shape of an octagon, placing parts are arranged on both sides of the protrusion parts, and a water flow groove and a recessed part are formed in the surface of the tile.

CONSTITUTION: A protrusion part 4 is formed on the upper end of a tile 1. Placing parts 5a and 5b are formed on both sides of the protrusion part 4. Four water flow grooves 7a-7d are formed in the surface, except the protrusion part 4 and the placing parts 5a and 5b, of the tile 1. In this case, the protrusion parts 4 are arranged toward the upper end of a roof in a zigzagging state from the lower part of roof to the upper part thereof. The water flow grooves of the tiles 1 are interconnected in a vertical direction. The water flow grooves 7a-7d are then connected to the recessed parts 9a-9d. In which case, since a gap between the tiles is increased owing to the recessed part, water is overlapped with each other by a surface tension, most of rainwater flowing down through the water flow groove 5 flows down in the water flow groove without being held in the gap. This constitution reduces the possibility of rainwater flowing over the upper edge of the tile and leakage of water occurring.