This invention provides a flue gas treating process for removing sulfur oxides and dust from exhaust gas containing sulfur oxides and dust by using an absorption tower into which an absorbing fluid containing an alkaline agent is sprayed, comprising the steps of equipping the absorption tower with integrally formed dust collection means comprising dust collecting plates and discharge electrodes, and with dust separation means for sweeping off the dust collected by the dust collection means; and treating the exhaust gas in the dust collection means and subsequently cleaning the exhaust gas in the absorption tower, whereby desulfurization and dust removal are effected while sweeping off the collected dust by the dust separation means. Thus, desulfurization and dust removal can be effected in a simple manner, and the capacity of an electrostatic precipitator installed on the upstream side can be reduced.