An exhaust purification system comprising: a NOx-occlusion-reduction-type catalyst that is provided in an exhaust passage of an internal combustion engine and occludes NOx in exhaust when the exhaust is in a lean state and reduces and purifies the occluded NOx when the exhaust is in a rich state; characterised by first NOx purge control means for executing NOx purge of reducing and purifying NOx occluded in the NOx-occlusion-reduction-type catalyst by putting the exhaust by into the rich state by fuel injection control of at least one of post injection and exhaust pipe injection, in a case where a catalyst temperature of the NOx-occlusion-reduction-type catalyst is equal to or higher than a catalyst temperature threshold value and a NOx occlusion amount in the NOx-occlusion-reduction-type catalyst is equal to or greater than an occlusion amount threshold value, wherein the higher the catalyst temperature above the catalyst temperature threshold value, the larger the number of times the fuel injection is repeated, and second NOx purge control means for executing the NOx purge even when the catalyst temperature is lower than a catalyst temperature threshold value, in a case where the NOx occlusion amount in the NOx-occlusion-reduction-type catalyst is equal to or greater than the occlusion amount threshold value, a fuel injection amount resulting from an accelerator operation is equal to or greater than a predetermined injection amount threshold value, and an exhaust temperature of exhaust to be introduced into the NOx-occlusion-reduction-type catalyst is equal to or higher than a predetermined exhaust temperature threshold value. a NOx-occlusion-reduction-type catalyst that is provided in an exhaust passage of an internal combustion engine and occludes NOx in exhaust when the exhaust is in a lean state and reduces and purifies the occluded NOx when the exhaust is in a rich state; characterised by first NOx purge control means for executing NOx purge of reducing and purifying NOx occluded in the NOx-occlusion-reduction-type catalyst by putting the exhaust by into the rich state by fuel injection control of at least one of post injection and exhaust pipe injection, in a case where a catalyst temperature of the NOx-occlusion-reduction-type catalyst is equal to or higher than a catalyst temperature threshold value and a NOx occlusion amount in the NOx-occlusion-reduction-type catalyst is equal to or greater than an occlusion amount threshold value, wherein the higher the catalyst temperature above the catalyst temperature threshold value, the larger the number of times the fuel injection is repeated, and second NOx purge control means for executing the NOx purge even when the catalyst temperature is lower than a catalyst temperature threshold value, in a case where the NOx occlusion amount in the NOx-occlusion-reduction-type catalyst is equal to or greater than the occlusion amount threshold value, a fuel injection amount resulting from an accelerator operation is equal to or greater than a predetermined injection amount threshold value, and an exhaust temperature of exhaust to be introduced into the NOx-occlusion-reduction-type catalyst is equal to or higher than a predetermined exhaust temperature threshold value.