An image reading device includes a document feeder and a reader. The document feeder includes a document tray and feeds an original document loaded on the document tray. The reader includes an original glass plate, a reading unit, and a document separating member. At least one of the document feeder and the reader is provided with a fan that creates an air flow. A first duct is provided in a housing of the reader. The document separating member is provided with a plurality of first discharge holes through which the air flowing through the first duct is discharged. A second duct is provided in a housing of the document feeder. The wall of the document feeder is provided with a plurality of second discharge holes through which the air flowing through the second duct is discharged.