An exhaust gas purifying apparatus provided in an exhaust passage (60) connected with an engine (50) includes an upstream catalyst (20) that is provided in the exhaust passage (60), and that removes NOx; a downstream catalyst (30) that is provided downstream of the upstream catalyst (20) in the exhaust passage (60); and supply means (40) for supplying an oxygen-activating component to a portion of the exhaust passage (60) located between the upstream catalyst (20) and the downstream catalyst (30). In the exhaust gas purifying apparatus, the upstream catalyst (20) removes NOx, and then an oxygen-activating component is supplied to the exhaust gas. Further, the downstream catalyst (30) removes a hydrocarbon compound contained in the exhaust gas.