The invention discloses a nitrogen adding star wheel apparatus and a nitrogen adding method for adding nitrogen to bottled edible oil. The nitrogen adding star wheel apparatus comprises a fixed shaft, a fixed handle, a gas inlet pipe, a gas inlet hollow shaft, a star wheel lower plate, a star wheel support column arranged above the star wheel lower plate and used for supporting a nitrogen adding star wheel apparatus control mechanism, a star wheel upper plate arranged above the star wheel support column, a pneumatic mechanical valve arranged between the star wheel upper plate and the star wheel lower plate and used for contacting an edible oil bottle so as to control the turning on or turning off of a gas path, a nitrogen spraying nozzle arranged above the pneumatic mechanical valve and used for adding nitrogen to the edible oil bottle, a sliding block arranged below the nitrogen spraying nozzle and used for fixing and driving the nitrogen spraying nozzle to slide, and a cam disk arranged on the gas inlet hollow shaft and used for controlling the sliding block to drive the nitrogen spraying nozzle to radially move. According to the present invention, the nitrogen is added to the edible oil bottle so as to replace the oxygen in the bottle, such that the oxidation is slowed down, and the storage time of the edible oil is prolonged.