In an image forming apparatus that uses a charging unit to charge a photosensitive drum, forms an electrostatic latent image by carrying out image exposure according to image information, and transfers to a paper the electrostatic latent image by developing the electrostatic latent image into a visible image using a developer so that the image information is presented, an exhaust duct 33 for exhausting air that contains ozone produced within a drum unit 30, which includes a photosensitive drum 3 and a charging unit 5, and a duct 32 for taking in air, which draws in fresh air, are provided within the drum unit 30 so that ventilation of the drum unit 30 can be carried out with excellent efficiency.