To provide an exhaust emission control system capable of suppressing an excessive temperature rise in an exhaust emission control device when an additive agent is added to exhaust air.

This system is provided with the exhaust emission control device installed in an exhaust passage of an internal combustion engine and an addition valve which adds the additive agent to exhaust air flowing into the exhaust emission control device. The system executes a temperature rise control which increases an actual temperature of the exhaust emission control device to the target temperature by adding the additive agent through the open and driven addition valve. In execution of the temperature rise control, a learning coefficient Gk is learned then recorded and updated in each predetermined period to correct a stationary deviation between the actual temperature of the exhaust emission control device and the target temperature. If a temperature rise width W1 of the actual temperature to be targeted in the execution of the temperature rise control is bigger than a temperature rise width W2 in recording the latest learning coefficient Gk (S301: YES), an additive amount of the additive agent is corrected and reduced by using the corrected learning coefficient Gk (S303, S304).