The present invention provides a method and an apparatus for analyzing nitrogen in a gas, in which the concentration of nitrogen can be continuously measured with good sensitivity without wasting a sample gas. At least one wavelength for measuring a concentration of nitrogen according to the intensity of a light generated by discharge, is selected from a group consisting of 215±2 nm, 226±2 nm, 238±2 nm, 242±2 nm, 246±1 nm, 256±2 nm, 260±2 nm, 266±2 nm, 271±1 nm, 276±4 nm, 285±2 nm, 294±1 nm, and 300±2 nm.