An antioxidant gas blow-off unit includes: a base portion configured as a hollow plate having an antioxidant gas flow passage formed therein; a hole that is provided in the base portion to allow a capillary to be inserted therein or removed therefrom and that communicates with the antioxidant gas flow passage; and a heater mounted on an outer surface of the base portion. The antioxidant gas flow passage includes a first flow passage provided in the vicinity of the outer surface of the base portion on which the heater is mounted. This antioxidant gas blow-off unit to be installed in a wire bonding apparatus heats free air balls effectively with a compact structure.