Abstract: An exhaust emission control device includes a single filter assembly composed of a pair of side plates respectively formed in an L-letter shape in cross-section and integrally assembled in a square framework having inlet and outlet openings, and a plurality of ceramic filter elements aligned in parallel within the square framework and clamped by the side plates. The filter elements are each made of porous ceramic material and have a thin-walled cellular structure square in cross-section formed with a plurality of axially extending passages separated from each other by thin partition walls, wherein a first group of the passages are closed at their one ends in a checked pattern and opened at their other ends to introduce therein exhaust gases to be purified, while a second group of the passages are opened at their one ends to discharge purified gases therefrom and closed at their other ends in a checked pattern.