A method for treating a gas characterized in that a low temperature plasma is generated in the presence of a metallic oxide oxidation catalyst, and an apparatus for treating a gas characterized by containing a low temperature plasma-generating unit carrying a metallic oxide oxidation catalyst are disclosed. According to the treating method and the treating apparatus, harmful components (such as carbon monoxide or a volatile organic compound) in a gas to be treated can be efficiently oxidized and rendered harmless, a foul odor may be rendered odorless, and further, microorganisms may be removed from and reduced in the treated gas.