A purge nozzle unit 1 includes a nozzle main body 2 including a trunk 41 and a collar section 8 protruding outward from the trunk 41 and a holder 3 including a side wall 31 that is in slidable contact with an outward face of the collar section 8 and a bottom wall 33 having a through hole 32 with which an outward face of the trunk 41 is in slidable contact and is configured such that a vent 30 in communication with the outside is formed in the holder 3 and the nozzle main body 2 is vertically moved relative to the holder 3 by regulating a pressure in a pressure-regulated space S formed between the nozzle main body 2 and the holder 3 and in communication with the vent 30.