To method for removing NOx in exhaust gas produced by burning fuel in a contacting manner without deterioration of catalysts by burning the fuel under periodic rich/lean conditions even in the existence of oxygen, sulfur oxide or water and even at a wide range of reaction temperature, and its device.

The method for removing nitrogen oxide in exhaust gas in a contacting manner by burning fuel supplied under the periodic rich/lean conditions and putting the produced exhaust gas in contact with the catalysts comprises putting the exhaust gas in contact with an upstream catalyst having a first catalytic component of ceria and a second catalytic component of palladium as upstream catalytic components and then putting it in contact with a downstream catalyst having a first catalytic component of ceria and a second catalytic component of rhodium as downstream catalytic components.