An exhaust gas processing apparatus that processes exhaust gas, comprising: a reaction tower that includes an internal space extending in a height direction from a bottom portion side where the exhaust gas is introduced to a top portion side where the exhaust gas is emitted; a trunk tube that extends in the height direction in the internal space of the reaction tower and transports a liquid; a plurality of branch tubes that are provided extending from an outer side surface of the trunk tube toward an inner side surface of the reaction tower, each include an ejecting section that ejects the liquid supplied from the trunk tube, and are provided at positions at different heights; and an exhaust gas introducing section that causes the exhaust gas to be introduced into the reaction tower in a manner to circulate the exhaust gas in a spiral along the side surface of the reaction tower, wherein ejection regions of the liquid where the liquid is ejected from the respective ejecting sections of branch tubes that are adjacent in the height direction include a region in which the ejection regions partially overlap in an overhead view as seen from the height direction, and characterized in that intervals between the plurality of branch tubes in the height direction are smaller in a top portion of the reaction tower where the exhaust gas is emitted than in a bottom portion of the reaction tower where the exhaust gas is introduced, and/or among the plurality of branch tubes angles formed between branch tubes that are adjacent in the height direction are smaller in a top portion of the reaction tower where the exhaust gas is emitted than in a bottom portion of the reaction tower where the exhaust gas is introduced, and the ejecting sections are provided in the branch tubes and are configured for ejecting liquid particles having diameters that are smaller in a top portion of the reaction tower where the exhaust gas is emitted than in a bottom portion of the reaction tower where the exhaust gas is introduced, such that the number of particles in the ejected liquid per unit volume is greater in the top portion of the reaction tower where the exhaust gas is emitted than in the bottom portion of the reaction tower where the exhaust gas is introduced. a reaction tower that includes an internal space extending in a height direction from a bottom portion side where the exhaust gas is introduced to a top portion side where the exhaust gas is emitted; a trunk tube that extends in the height direction in the internal space of the reaction tower and transports a liquid; a plurality of branch tubes that are provided extending from an outer side surface of the trunk tube toward an inner side surface of the reaction tower, each include an ejecting section that ejects the liquid supplied from the trunk tube, and are provided at positions at different heights; and an exhaust gas introducing section that causes the exhaust gas to be introduced into the reaction tower in a manner to circulate the exhaust gas in a spiral along the side surface of the reaction tower, wherein ejection regions of the liquid where the liquid is ejected from the respective ejecting sections of branch tubes that are adjacent in the height direction include a region in which the ejection regions partially overlap in an overhead view as seen from the height direction, and characterized in that intervals between the plurality of branch tubes in the height direction are smaller in a top portion of the reaction tower where the exhaust gas is emitted than in a bottom portion of the reaction tower where the exhaust gas is introduced, and/or among the plurality of branch tubes angles formed between branch tubes that are adjacent in the height direction are smaller in a top portion of the reaction tower where the exhaust gas is emitted than in a bottom portion of the reaction tower where the exhaust gas is introduced, and the ejecting sections are provided in the branch tubes and are configured for ejecting liquid particles having diameters that are smaller in a top portion of the reaction tower where the exhaust gas is emitted than in a bottom portion of the reaction tower where the exhaust gas is introduced, such that the number of particles in the ejected liquid per unit volume is greater in the top portion of the reaction tower where the exhaust gas is emitted than in the bottom portion of the reaction tower where the exhaust gas is introduced.