To provide a mechanism for cleaning a gas capable of preventing the discharge of chlorine gas into a gas phase to the extent practicable.

The mechanism for cleaning a gas including a storage tank (2) for storing electrolytic water (1) and a scrubber (3) disposed thereabove is characterized by spraying the electrolytic water (1) in the scrubber (3) and aerating the electrolytic water (1) present in the storage tank (2) with a gas to be cleaned. Since the electrolytic water (1) present in the storage tank (2) is aerated with the gas and the aerating gas removes heat if the temperature of the electrolytic water (1) rises, which gas is subsequently discharged from the water surface, the water temperature is prevented from rising, and thereby chlorine dissolved in the water is prevented from evaporating as chlorine gas.