An exhaust purification system comprising: an NOx occlusion reduction type catalyst that is provided in an exhaust passage of an internal combustion engine to purify a nitrogen compound in an exhaust gas; an intake air amount detecting unit that detects an actual intake air amount of the internal combustion engine; a catalyst regeneration control unit that performs an SOx purge control for recovering the NOx occlusion reduction type catalyst from SOx-poisoning, using in combination both of: an air system control in which a target intake air amount necessary for lowering the exhaust gas to a predetermined first target excess air ratio is set based on an operating state of the internal combustion engine and the intake air amount of the internal combustion engine is feedback-controlled based on the target intake air amount; and an injection system control in which a target injection increase amount necessary for lowering the exhaust gas to a predetermined second target excess air ratio is set based on the target intake air amount and a fuel injection amount is feedback-controlled based on the target injection increase amount; a prohibition unit that prohibits execution of the SOx purge control according to the operating state of the internal combustion engine; characterized in that a catalyst warming control unit that executes a catalyst warming control in which an air system of the internal combustion engine is open-loop controlled during a period in which the SOx purge control is prohibited by the prohibition unit, the fuel injection amount is feedback-controlled, and thus the exhaust gas is maintained at a predetermined temperature, wherein the catalyst regeneration control unit executes the injection system control by switching the target intake air amount used for setting the target injection increase amount into an actual intake air amount detected by the intake air amount detecting unit when returning from the catalyst warming control to the SOx purge control. an NOx occlusion reduction type catalyst that is provided in an exhaust passage of an internal combustion engine to purify a nitrogen compound in an exhaust gas; an intake air amount detecting unit that detects an actual intake air amount of the internal combustion engine; a catalyst regeneration control unit that performs an SOx purge control for recovering the NOx occlusion reduction type catalyst from SOx-poisoning, using in combination both of: an air system control in which a target intake air amount necessary for lowering the exhaust gas to a predetermined first target excess air ratio is set based on an operating state of the internal combustion engine and the intake air amount of the internal combustion engine is feedback-controlled based on the target intake air amount; and an injection system control in which a target injection increase amount necessary for lowering the exhaust gas to a predetermined second target excess air ratio is set based on the target intake air amount and a fuel injection amount is feedback-controlled based on the target injection increase amount; a prohibition unit that prohibits execution of the SOx purge control according to the operating state of the internal combustion engine; characterized in that a catalyst warming control unit that executes a catalyst warming control in which an air system of the internal combustion engine is open-loop controlled during a period in which the SOx purge control is prohibited by the prohibition unit, the fuel injection amount is feedback-controlled, and thus the exhaust gas is maintained at a predetermined temperature, wherein the catalyst regeneration control unit executes the injection system control by switching the target intake air amount used for setting the target injection increase amount into an actual intake air amount detected by the intake air amount detecting unit when returning from the catalyst warming control to the SOx purge control.