To provide a stair frame by which a leg body at a string bottom edge can be fixed to a scaffold cloth board.

A plurality of step boards 9 are attached between a pair of strings 8 at a prescribed interval, a hook is anchored to a top edge of the string 8 to enable the hook to be latched to a horizontal member of an upper scaffolding, and a leg body 12 for installing a scaffold cloth board 5 is provided at the lower ends of the strings 8. The leg body 12 is provided with an engaging bar body 22. The engaging bar body 22 extends upwardly to the vicinity of a central position between the lowermost stage step board 9 among the plurality of step boards 9 and the scaffold cloth board 5, and passes downwardly through the scaffold cloth board 5, with a lower end of the engaging bar body being abutted to the underside of the scaffold cloth board 5. The engaging bar body 22 is vertically movable with respect to the leg body 12, and the leg body 12 is provided with an elastic body 22b for making the lower end of the engaging bar body 22 abut on the underside of the scaffold cloth board 5 at a position where the engaging bar body 22 extends to the vicinity of the central position between the lowermost stage step board 9 and the scaffold cloth board 5.