To solve the problem requiring to separately apply waterproofing to a roof backing when laying a roof tile on a gentle slope roof.

A tail side part 6a in flashing 6 running along the tail side and the insertion side of a trough part 2 is formed so as to gradually become high to the central side of the trough part 2. A clearance recess part 8 for housing an upper part of the tail side part 6a in the flashing 6 is formed on the reverse of the trough part 2. Flashing projection strips 10 and 10a are formed on a tail side upper surface of the trough part 2. A pantile 1 provided with flashing projection strips 11, 11a, 12, and 12a is laid so as to run along a head side part and the tail side part in an outer peripheral part of the clearance recess part 8. Wind blowing in from clearance between the upper-lower pantiles 1 and 1 is reduced in force by meandering by colliding with the flashing projection strips 10 and 10a of an upper surface of the lower pantile 1, the head side flashing projection strips 11 and 11a on the reverse of the upper pantile 1, the tail side part 6a of the flashing 6 of the lower pantile 1, and the tail side flashing projection strips 12 and 12a on the reverse of the upper pantile 1, and since inclusion moisture is stuck and removed, even if a superposing dimension is set constant regardless of a roof pitch internal intrusion of the wind including the moisture can be checked.