An exhaust purification system comprising: a NOx-occlusion-reduction-type catalyst that is provided in an exhaust passage of an internal combustion engine , 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; catalyst regeneration means for performing catalyst regeneration processing of setting the exhaust in the rich state and reducing and purifying the NOx occluded in the NOx-occlusion-reduction-type catalyst ; and inhibition means for inhibiting performance of the catalyst regeneration processing by the catalyst regeneration means when the internal combustion engine becomes a motoring state in which fuel injection is stopped, and inhibiting, when the internal combustion engine has started fuel injection during the inhibition, performance of the catalyst regeneration processing from start of the fuel injection until a predetermined time period has elapsed, characterised in that : when a decrease rate in a fuel injection amount of the internal combustion engine decreases below a predetermined lower limit threshold value, the inhibition means inhibits performance of the catalyst regeneration processing by the catalyst regeneration means, and when the decrease rate in the fuel injection amount of the internal combustion engine recovers to the lower limit threshold value or greater during the inhibition, the inhibition means inhibits performance of the catalyst regeneration processing from when the decrease rate in the fuel injection amount of the internal combustion engine has recovered to the lower limit threshold value or greater until a predetermined time period has elapsed. a NOx-occlusion-reduction-type catalyst that is provided in an exhaust passage of an internal combustion engine , 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; catalyst regeneration means for performing catalyst regeneration processing of setting the exhaust in the rich state and reducing and purifying the NOx occluded in the NOx-occlusion-reduction-type catalyst ; and inhibition means for inhibiting performance of the catalyst regeneration processing by the catalyst regeneration means when the internal combustion engine becomes a motoring state in which fuel injection is stopped, and inhibiting, when the internal combustion engine has started fuel injection during the inhibition, performance of the catalyst regeneration processing from start of the fuel injection until a predetermined time period has elapsed, characterised in that : when a decrease rate in a fuel injection amount of the internal combustion engine decreases below a predetermined lower limit threshold value, the inhibition means inhibits performance of the catalyst regeneration processing by the catalyst regeneration means, and when the decrease rate in the fuel injection amount of the internal combustion engine recovers to the lower limit threshold value or greater during the inhibition, the inhibition means inhibits performance of the catalyst regeneration processing from when the decrease rate in the fuel injection amount of the internal combustion engine has recovered to the lower limit threshold value or greater until a predetermined time period has elapsed. <EOS>