Abstract: Removal of fine particles by oxidation or/and sulfur poisoning recovery control may be required when an internal combustion engine has been in an extremely low load state for a predetermined period or more. In this case, the engine speed of the internal combustion engine (1) is adjusted to a range where the temperature of a filter (20) can be raised by heat-up control. The heat-up control is then executed by a filter temperature control means to raise the temperature of the filter (20) to a predetermined value. When the filter (20) reaches the predetermined temperature by means of low-temperature combustion, post-injection, VIGOM-injection, addition of 10 fuel to an exhaust system and the like, removal of fine particles by oxidation or/and sulfur poisoning recovery control for eliminating sulfur poisoning of a NOx absorbent are conducted.