EXHAUST PURIFYING APPARATUS FOR INTERNAL COMBUSTION ENGINE

An exhaust purifying apparatus for an internal combustion engine (1) includes a NOx removing catalyst (41), an oxidation catalyst (51), and a NOx amount calculating section (80), which is configured to calculate the amount of NOx contained in exhaust gas that has passed through the oxidation catalyst. The apparatus includes a controller (80) configured to execute an abnormality diagnosis process for determining the existence of an abnormality in the NOx removing catalyst if NOx removal efficiency obtained from the amount of NOx is less than or equal to a predetermined value. The controller (80) is configured to execute the abnormality diagnosis process after executing a desorption process for desorbing unburned fuel adsorbed by the NOx removing catalyst if an execution condition of the abnormality diagnosis process is met.