An air-blowing unit includes a blower unit including an irreversible fan, a first blower-side duct connected to an inlet port of the blower unit, a second blower-side duct connected to an air discharge port of the blower unit, a first air opening-side duct including a first air opening, a second air opening-side duct including a second air opening, and an air passage switching device disposed between the blower-side ducts and the air opening-side ducts. The air passage switching device switches air passage connection between the blower-side ducts and the air opening-side ducts.