This invention is intended to ensure that an exhaust gas purification device with an NOx storage reduction catalyst and a particulate filter is able to fully utilize an original NOx storage capability of the NOx storage reduction catalyst. For this end, in addition to the filter 40 disposed upstream relative to the NOx storage reduction catalyst 22, the purification device includes a fuel supply element 42 for supplying a fuel so that the fuel is mixed with exhaust gas that flows into the filter, and an ozone feeder 30 for supplying ozone so that the ozone is mixed with exhaust gas that flows into the NOx storage reduction catalyst at a downstream position relative to the filter 40.