To provide a method and a device for purifying nitrogen in which impurities such as methane, carbon monoxide and carbon dioxide can be removed at the same time.

A getter alloy consisting of Zr-V-Fe, Zr-Fe and Zr as principal components is reacted with nitrogen at 200-450°C in a state that the air outside is cut off or in high vacuum to prepare a nitrided getter. The lower part of a nitrogen purifying column (the lower column when double columns are used) is filled with the prepared nitrided getter and the upper part (the upper column when double columns are used) is filled with a Pd/Al2O3 catalyst. The methane component in the nitrogen stream to be purified at 200-450°C is oxidized (if necessary, while supplying oxygen equivalent to methane) and then the impurities such as water, carbon dioxide, carbon monoxide and oxygen are removed by the nitrided getter.