The present invention provides an exhaust gas purifying device which can sufficiently perform HC purification even if a lean NOx catalyst included in a metal substrate is used. The exhaust gas purifying device comprises, in an exhaust passage (2) in an internal combustion engine (1) along a flowing direction (9) of the exhaust gas, a lean NOx catalyst (3) including a catalyst layer (7) which purifies nitrogen oxide contained in the exhaust gas under a hyperoxia atmosphere and a metal honeycomb (5), the lean NOx catalyst having the catalyst layer (7) supported within the metal honeycomb (5); and a reaction catalyst (4) for subjecting to an oxidation reaction at least hydrocarbon contained in the exhaust gas.