In an internal combustion engine including an NSR catalyst and an SCR, to provide an exhaust purifying system that can limit aggravation of emissions by allowing the SCR to recover effectively from degraded performance caused by poisoning. An exhaust purifying system for an internal combustion engine capable of a lean burn operation includes an NSR catalyst disposed in an exhaust passage of the internal combustion engine; an SCR disposed downstream of the NSR catalyst; means for detecting sulfur poisoning of the SCR; and means for increasing a bed temperature of the SCR when the poisoning detecting means detects sulfur poisoning of the SCR. The temperature increasing means includes bank control, stoichiometric control, and rich spike control, any one of which is selected for performance according to an operating condition of the internal combustion engine.