an apparatus and method for deodorizing a gas mixture including air and a malodorous substance having a flow passage for the gas mixture and a fan for inducing air flow in a predetermined direction through the passage . an ultraviolet lamp for generating uv rays below a critical wavelength is in the flow passage for generating ozone from the air in the gas mixture . an ozone - decomposing catalyst layer is in the passage for contacting the gas mixture , and an ozone - decomposing ultraviolet lamp for generating uv rays above critical wavelength is positioned to irradiate the layer directly . the intensity of the radiation of the two layers is controlled to avoid the discharge of ozone from the downstream end of the passage .