The effects of pre-adsorption of NO2 on the enhancement of the adsorption of NO on H-type zeolite are investigated to develop a fixed-bed adsorption process for removing low concentration NO effectively. The concentration of NOx in the effluent gas from a zeolite column was analyzed by a chemiluminescence method, where the concentration of the NOx at the inlet was adjusted to be between 0 to 1,000 ppm. It was found that the amount of NO adsorbed increases thirty to forty times when NO2 is preadsorbed on H-type zeolite. The amount of NO adsorbed depends on the concentration of NO2 Pre adsorbed, the concentration of NO supplied, and column temperature. 100% removal of No can be achieved when the concentration of NO is lower than 1,000 ppm and that of NO2 at the inlet during pre-adsorption is lower than 300 ppm. The extent of NO removal was similar for each diluent gas, nitrogen or helium. Based on these results, an adsorption process was proposed for the removal of NOx.