An exhaust purification system includes: an NOx reduction type catalyst, which is provided in an exhaust system of an internal combustion engine and reduces and purifies NOx in an exhaust gas; and a regeneration treatment unit, which recovers an NOx purification capacity of the NOx reduction type catalyst by lowering an excess-air-ratio of the exhaust gas to a predetermined target excess-air-ratio, wherein the regeneration treatment unit includes: a target setting unit, which sets a target intake air amount that is required for setting the exhaust gas to the target excess-air-ratio, based on a fuel injection amount of the internal combustion engine; and an air-system controller, which controls at least one of an intake air amount and an exhaust recirculating amount of the internal combustion engine, in response to the target intake air amount input from the target setting unit.