An image-reading unit includes an original document conveyor that includes a first original document tray to hold an original document to be read, a first original document feeding port to feed the original document placed on the first original document tray, and an original document conveying path to convey the original document from the first original document feeding port to an original document discharging port. The original document conveyor further includes an openable second original document tray attached near an intermediate portion of the original document conveying path to hold an original document when opened, and a second original document feeding port to feed the original document on the second original document tray. The image-reading unit further includes an image reader to read an image of the original document being conveyed along the original document conveying path.