a reactor containment vessel of the present invention has a primary reactor containment vessel disposing a dry well for storing a reactor pressure vessel , a wet well for storing a pressure suppression pool , and an equipment room disposing below said pressure suppression pool inside thereof . further , the primary reactor containment vessel includes an outer cylindrical wall reaching to a base mat from a top slab of the primary reactor containment vessel and facing the drywell , the pressure suppression pool and the equipment room respectively , an inner cylindrical wall facing the pressure suppression pool and the equipment room respectively , and a pressure suppression pool floor partitioning among the pressure suppression pool and the equipment room , and an outside portion of the outer cylindrical wall , an inside portion of the inner cylindrical wall , an outside portion of the ceiling and a lower portion of the pressure suppression pool floor are formed of a steel plate reinforced concrete respectively . the reactor containment vessel can contribute to shorten construction period and thereby improve economic efficiency of nuclear power generation facilities .