An image forming apparatus includes a photosensitive drum, an optical unit provided below the photosensitive drum and including a cover glass for transmitting light emitted toward the photosensitive drum, and a cleaning member configured to clean a surface of the cover glass. The cleaning member includes a cleaning sheet configured to move foreign substances on the surface, and a wiping member configured to wipe foreign substances from the surface. The cleaning sheet and the wiping member move in contact with the surface of the cover glass when the cleaning member cleans the surface. The wiping member moves in contact with a portion of the surface of the cover glass after the cleaning sheet moves in contact with the portion. Accordingly, the cover glass can be reliably cleaned even when an unexpectedly large number of foreign substances that vary in particle size and shape adhere to the cover glass.