To reduce a high light work to improve working efficiency by providing a cutout part fittable from the outer circumference of a beam projecting position to the steel pillar of a pillar member, and standingly providing a handrail part in the outer circumferential range of a scaffolding board part superposed on the upper face of the beam and a scaffolding board part to be the outer circumference of the steel pillar when positioning the steel pillar in the cutout part.

A member in which beam parts 3 are previously welded to a steel pillar 1 provided with connecting flange parts 2 on the upper/lower ends is used, and the beams 3 of the adjoining members are connected together through a connecting plate D, a connecting bolt B, and the like to assemble a tower main body. In this case, for a scaffold E, in addition to assemble a part of the steel tower main body by the pillar members, the steel pillar 1 is positioned in the cutout part of a scaffolding board part 4, and the scaffolding board part 4 is placed on the upper face of the beam 3 of the uppermost part and connected to it. One section part with the scaffold is lifted by a crane or the like, and by connecting together the flange parts of the upper/lower steel pillars 1 in order to assemble. Therefore, by reducing a high lift work, safety and working efficiency can be improved.