Provided is an air purge unit capable of removing contamination of a lens surface of a photoelectric sensor with a small air supply amount. This air purge unit 2 is provided with: a housing 30; an air supply port 31 for supplying air into the housing 30; and a plurality of air blow-out ports 32 arranged on a side wall of the housing 30 and blowing air to a lens surface 11a of a photoelectric sensor 1.