To provide a spacing adjustment tool of roof materials and a construction method of the roof materials which makes the clearance between adjacent roof materials constant and facilitates execution of the roof materials.

The spacing adjusting tool has a platy clearance forming part 13 interposed between right and left mutually adjacent roof materials 3, 4 and an engagement part 14 engaging with the shoulder 6 of the roof materials 3, 4 so that the clearance forming part 13 does not slip off in the roof stream direction. One end face in the thickness direction of the clearance forming part 13 shapes a first contact part 15 bringing into contact with the side end face 8 of the roof materials 3, 4 and the other end face in the thickness direction of the clearance forming part 13 shapes a second contact part 16 bringing into contact with the side end face 8 of the other roof materials 3, 4.