An exhaust purification system comprising: a NOx-occlusion-reduction-type catalyst that is provided in an exhaust system of an internal combustion engine and occludes NOx in exhaust flowing in the exhaust system when the exhaust is in a lean state and reduces and purifies the occluded NOx when the exhaust is in a rich state; catalyst regeneration means for executing catalyst regeneration processing of enriching the exhaust and reducing and purifying the NOx occluded in the NOx-occlusion-reduction-type catalyst; prohibition means for, when at least one of a plurality of prohibition conditions is fulfilled, prohibiting execution of the catalyst regeneration processing by the catalyst regeneration means even when a catalyst regeneration processing start request is issued, and continuing means for, when a specific prohibition condition, which is a part of the plurality of prohibition conditions, is fulfilled during the execution of the catalyst regeneration processing, invalidating the prohibition means and continuing the catalyst regeneration processing by the catalyst regeneration means, wherein the prohibition means prohibits execution of the catalyst regeneration processing by the catalyst regeneration means even when a catalyst regeneration processing start request is issued in a case where a catalyst temperature of the NOx-occlusion-reduction-type catalyst is lower than a predetermined catalyst activation temperature, and the continuing means invalidates the prohibition means and continues the catalyst regeneration processing by the catalyst regeneration means in a case where the catalyst temperature of the NOx-occlusion-reduction-type catalyst becomes lower than the predetermined catalyst activation temperature during the execution of the catalyst regeneration processing after the catalyst regeneration processing is started at a point of time at which the catalyst temperature of the NOx-occlusion-reduction-type catalyst is equal to or higher than the predetermined catalyst activation temperature. a NOx-occlusion-reduction-type catalyst that is provided in an exhaust system of an internal combustion engine and occludes NOx in exhaust flowing in the exhaust system when the exhaust is in a lean state and reduces and purifies the occluded NOx when the exhaust is in a rich state; catalyst regeneration means for executing catalyst regeneration processing of enriching the exhaust and reducing and purifying the NOx occluded in the NOx-occlusion-reduction-type catalyst; prohibition means for, when at least one of a plurality of prohibition conditions is fulfilled, prohibiting execution of the catalyst regeneration processing by the catalyst regeneration means even when a catalyst regeneration processing start request is issued, and continuing means for, when a specific prohibition condition, which is a part of the plurality of prohibition conditions, is fulfilled during the execution of the catalyst regeneration processing, invalidating the prohibition means and continuing the catalyst regeneration processing by the catalyst regeneration means, wherein the prohibition means prohibits execution of the catalyst regeneration processing by the catalyst regeneration means even when a catalyst regeneration processing start request is issued in a case where a catalyst temperature of the NOx-occlusion-reduction-type catalyst is lower than a predetermined catalyst activation temperature, and the continuing means invalidates the prohibition means and continues the catalyst regeneration processing by the catalyst regeneration means in a case where the catalyst temperature of the NOx-occlusion-reduction-type catalyst becomes lower than the predetermined catalyst activation temperature during the execution of the catalyst regeneration processing after the catalyst regeneration processing is started at a point of time at which the catalyst temperature of the NOx-occlusion-reduction-type catalyst is equal to or higher than the predetermined catalyst activation temperature.