In order to maintain a high NOx purification rate of a NOx reduction catalytic converter even in the case in which an NOx emission amount from an engine changes suddenly, in an exhaust emission purifying apparatus for an engine that reduces and purifies NOx in exhaust gas using ammonia generated from an injection-supplied urea aqueous solution, after engine starting, when an exhaust temperature exceeds a predetermined temperature T (step S1), an amount of urea aqueous solution corresponding to an actual engine operating state is injection-supplied (steps S3 to S5). On the other hand, at a change of the transmission speed ratio based on a driver's shift operation, an engine operating state after the change of the transmission speed ratio is predicted (steps S2, S6), and an amount of urea aqueous solution corresponding to the predicted engine operating state is injection-supplied before the change of the transmission speed ratio is completed (steps S7, S8).