To surely and visually affirm with ease whether a compression spring is compressed as specified, and let a pole body be surely held with no fear of coming out of a place between paired mounting parts accidentally.

In a prop-up pole, the compression of a compression spring 31 with a pole body adjusted in elongation, thereby allows paired receiving seats 17 to be pressed to and brought into contact with paired mounting parts mutually faced to each other by making use of the stability of the compression spring 31 in such a way that the pole body is held in a place between paired mounting parts while being propped up, and a display means 40 is provided, which determines and indicates whether the compression spring 31 is compressed as specified when the pole body is held in a place between the paired mounting parts.