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