To make it possible to stably lay a scaffold board over a stand even on stairways, slopes or the like.

Supporting pipes 4, 4 are journalled to supporting boards 3, 3 of supporting members 2, 2, on which a scaffold board 20 is laid, so that they can freely make turning movement centering hinges 9, 9. The upper ends of a pair of right and left upper legs 7, 7 are welded to both lower ends on the longitudinal direction of the supporting pipes 4, 4. Lower legs 11, 11 are slidably provided in the upper legs 7, 7 and the lower ends of the pair of front rear lower legs 11, 11 are connected to each other by connecting members 17. Mutual maximum openings of the pair of right and left upper legs 7, 7 are regulated by journalling regulating members 10a, 10a between the pair of right and left upper legs 7, 7 in a foldable manner in two.