Abstract: An exhaust gas treatment method by which mercury contained in exhaust gas can be separated and removed efficiently and inexpensively. The method includes cooling an exhaust gas containing mercury in metal vapor phase by spraying water or other methods to condense mercury in the exhaust gas from metal vapor phase into metal liquid and thus to separate and remove mercury from the exhaust gas. When the exhaust gas is cooled by spraying water, the sprayed water is collected and separated into separated water and a solid containing mercury that has condensed to metal liquid, and mercury is recovered from the solid. The metal mercury particles that have condensed to metal liquid are dispersed in cooling water. The metal mercury particles can thus be easily separated and recovered by using a suitable separation device.