An exhaust gas purification system (1,1A) comprising NOx occlusion reduction type catalysts (22, 23) each having a catalytic metal and a NOx occlusion material which stores NOx when an air-fuel ratio of exhaust gas is in a lean state and releases the occluded NOx when the air-fuel ratio is in a rich state, wherein a high-temperature NOx occlusion reduction type catalyst in which a NOx occlusion material containing an alkali metal is supported and a low-temperature NOx occlusion reduction type catalyst in which a NOx occlusion material containing an alkaline earth metal is supported are disposed in series on an upstream side and a downstream side, respectively, wherein the high-temperature NOx occlusion reduction type catalyst is having a higher working temperature than the low-temperature NOx occlusion reduction type catalyst, and an oxidation catalyst is disposed on an upstream side of the high-temperature NOx occlusion reduction type catalyst, characterized in that high-temperature hydrocarbon addition means is disposed on an upstream side of the high-temperature NOx occlusion reduction type catalyst, low-temperature hydrocarbon addition means is disposed between the high-temperature NOx occlusion reduction type catalyst and the low-temperature NOx occlusion reduction type catalyst, wherein the high-temperature hydrocarbon addition means is having a higher working temperature than the low-temperature hydrocarbon addition means, a first NOx sensor is provided immediately after the high-temperature NOx occlusion reduction type catalyst, a second NOx sensor is provided immediately after the low-temperature NOx occlusion reduction type catalyst, the exhaust gas purification system (1, 1A) includes hydrocarbon supply control means for controlling the high-temperature hydrocarbon addition means and the low-temperature hydrocarbon addition means, and the hydrocarbon supply control means is configured such that when a temperature of the exhaust gas flowing into the oxidation catalyst is lower than a first determination temperature, a hydrocarbon is supplied only from the low-temperature hydrocarbon addition means and a feedback control of the amount of the hydrocarbon supplied is conducted by using a value detected by the second NOx sensor, when the temperature of the exhaust gas flowing into the oxidation catalyst is not lower than the first determination temperature but lower than a second determination temperature, a hydrocarbon is supplied from the high-temperature hydrocarbon addition means and a feedback control of the amount of the hydrocarbon supplied is conducted by using a value detected by the first NOx sensor, and also a hydrocarbon is supplied from the low-temperature hydrocarbon addition means and a feedback control of the amount of the hydrocarbon supplied is conducted by using a value detected by the second NOx sensor, and when the temperature of the exhaust gas flowing into the oxidation catalyst is not lower than the second determination temperature, a hydrocarbon is supplied only from the high-temperature hydrocarbon addition means and a feedback control of the amount of the hydrocarbon supplied is conducted by using a value detected by the first NOx sensor. when a temperature of the exhaust gas flowing into the oxidation catalyst is lower than a first determination temperature, a hydrocarbon is supplied only from the low-temperature hydrocarbon addition means and a feedback control of the amount of the hydrocarbon supplied is conducted by using a value detected by the second NOx sensor, when the temperature of the exhaust gas flowing into the oxidation catalyst is not lower than the first determination temperature but lower than a second determination temperature, a hydrocarbon is supplied from the high-temperature hydrocarbon addition means and a feedback control of the amount of the hydrocarbon supplied is conducted by using a value detected by the first NOx sensor, and also a hydrocarbon is supplied from the low-temperature hydrocarbon addition means and a feedback control of the amount of the hydrocarbon supplied is conducted by using a value detected by the second NOx sensor, and