To provide a flat roof tile capable of avoiding leaking of rain traveling along the rear face of a side edge section of a tile placed on a water receiver section of an adjoining tile.

A first Mizukiri (draining ridge) 13 is formed along the edge on the rear face of the side edge section of the tile 11 placed on the water receiver section 3 of the adjoining tile 11, a second Mizukiri 14 is formed as a protrusion in parallel with the first Mizukiri 13 and the two Mizukiris 13, 14 are formed to take position above the water receiver section 3 of the adjoining tile when the tiles are laid. Water traveling along the rear face of the edge section of the tile is drained by the Mizukiri 14 to drop onto the water receiver section 3. Thus, rain water is prevented from dropping onto a substrate of the roof.