Method and device for exhaust purification of an internal combustion engine

An exhaust purification device, including a NOx storing catalyst comprised of a precious metal catalyst and NOx absorbent, arranged in an engine exhaust passage, which increases the ratio of the nitrogen dioxide to the nitrogen monoxide produced when burning fuel under a lean air-fuel ratio when the NOx storing catalyst is not active compared with the time when the NOx storing catalyst is active under the same engine operating conditions and stores the nitrogen dioxide contained in the exhaust gas in the NOx absorbent at that time.