To stably regenerate a catalyst apparatus in an exhaust emission control device for an internal combustion engine.

An S recovery frequency expressing the degree of S generation from an S-poisoned occlusion type NOx catalyst 25 is calculated taking into consideration the remaining coefficient Rqv of sulfur component, and according to the S recovery frequency, the set temperature ZSTEMP for elevating a catalyst temperature is obtained. When the catalyst temperature Tcat becomes the ZSTEMP or above, the temperature of the occlusion type NOx catalyst 25 is elevated and further, an air/fuel ratio is enriched to release an occluded SOx and to recover an NOx occlusion ability.