A gasification gas treatment facility for treating a gasification gas obtained by gasification of a fuel includes: a first heat exchanger for performing heat exchange between a purified gas obtained by removing at least ammonia and hydrogen chloride from the gasification gas and steam at a saturation temperature; a second heat exchanger for performing heat exchange between the gasification gas and at least condensed water produced by the heat exchange in the first heat exchanger to produce the steam at the saturation temperature; and a circulation system for circulating a circulating fluid including at least one of the steam or the condensed water between the first heat exchanger and the second heat exchanger. The circulation system is configured to supply the circulating fluid including at least the condensed water at the saturation temperature produced in the first heat exchanger to the second heat exchanger.