To enable a curtain rail to be held under the folded condition on the wall surface side and the room inside space in an opening part to be effectively used.

There are provided a curtain rail 10 used to hang a curtain 60 and an arm rod 20 to mount the curtain rail 10 nearly horizontally so an opening frame, wall or the like, while the arm rod 20 is provided pivotably on the opening frame, wall or the like, or at least a portion 20' of the arm rod 20 provided on the opening frame, wall or the like and having the curtain rail 10 is adapted to pivot in a curtain rail hanging structure.