Abstract: Embodiments provide reusable support member capable of facilitating assembly and disassembly of a form, and a concrete placing form. A reusable support member supports outer side surfaces of concrete panels providing cavity as predetermined space for placing concrete includes horizontal rails with a length according to width of the panels, vertical rails with length according to height of the panels, and bolt and nut structures for locking the panels into inner direction of the cavity by penetrating intersections in which respectively parallel the horizontal and vertical rails are combined in lattice shape. Either of the horizontal and vertical rails relating to the intersections, include recesses capable of fitting in opposing rails by receiving a width and a part or all of a thickness of opposing rails. The rails are configured by channel steel or metal material with equivalent shape, and the rails contact the outer side surfaces at equal intervals.