The present invention provides an exhaust gas treatment process wherein exhaust gas containing mercury and sulfur dioxide is subjected to a desulfurization treatment in a desulfurizing absorption tower and then passed through a mist eliminator for removing and recovering mist from the desulfurized exhaust gas, the process including the step of removing mercury from the desulfurized exhaust gas by feeding thereto an oxidizing agent such as sodium hypochlorite and an antioxidant such as methanol unreactive with the oxidizing agent at a position upstream of the aforesaid mist eliminator.