Apparatus and method for purifying exhaust gases in automotive engines

An exhaust gas purifying apparatus applied to an automotive engine (10) that performs lean combustion is installed in a vehicle, to purify exhaust gas with a NOx storage reduction catalytic converter (22) located in an exhaust passage (18) of the engine. Determining means (40) for determining whether or not the vehicle has started to move; and a supplying means (40) for supplying the NOx storage reduction catalytic converter with a reduction agent when the determining means determines that the vehicle has started to move.