To enable the judgment of a forced regeneration time by the differential pressure before and after a filter sufficiently and accurately in an exhaust emission control device in which a PM contained in the exhaust emission of an engine is trapped by the filter, and the accumulated PM is burnt by a catalytic action.

The device is provided with a means to judge whether or not it is a necessary time to forcedly regenerate from a detected value of the differential pressure (S6 to S13 in the figure), a means to limit the judgment of the forced regeneration time based on the differential pressure to a specified operating state (S1 in the figure), a means to control an engine rotation into a specified differential detection rotational speed in the specified operation state (S2 to S5 in the figure), and a means to positively raise the temperature of an CR-DPF17 when the forced regeneration is judged as the necessary time (not illustrated).