A method for enlarging the particle diameters of sulfuric acid mists in waste gas and collecting the sulfuric acid mists in high efficiency is provided. A process for disposing waste gas containing sulfur oxides that introduces the waste gas in dry type electrostatic precipitator to remove dusts and then introduces the waste gas in a wet desulfurization apparatus to carry out desulfurization, wherein outside air with a flow rate at which the waste gas introduced in the wet desulfurization apparatus is the dew point of acid is taken in from an introducing tube to mix the outside air in the waste gas.