A nuclear reactor containment vessel cooling equipment has: a dry well cooler casing (14) in a containment vessel (1), having an opening at its top and a shutter (38) at its lower part; a heat transfer tube (13) arranged at an upper part in the dry well cooler casing (14); a forced cooling water circulation system (32a) for feeding cooling water from outside of the containment vessel (1) into the heat transfer tube (13) by a pump (32); a blower (16) for mobilizing gas around the heat transfer tube (13); an external pool container (35) arranged outside the containment vessel (1) and above the heat transfer tube (13) and containing cooling water; and a gravity-driven cooling system (36) to supply cooling water in the external pool container (35) into the heat transfer tube (13), utilizing gravity.