Nozzle Cleaning Unit And Nozzle Cleaning Method

According to one embodiment, a nozzle cleaning unit includes: a cleaning nozzle unit; a gas supply unit; and a regulator. The cleaning nozzle unit has a first ejection hole that opens in a ring shape to an inner wall surface of an insertion part into which the nozzle is inserted. The gas supply unit supplies gas to the first ejection hole. The regulator reduces a pressure of an atmosphere of the insertion part on a side opposite a side in which the nozzle is inserted, sandwiching a position where the first ejection hole is provided.