CATALYST REGENERATION PROCESSING APPARATUS

A catalyst regeneration processing apparatus for an internal-combustion engine includes an electronic control unit (60). The electronic control unit (60) is configured to determine whether a difference is less than or equal to a predetermined degree, the difference being a difference between a progression in the degree of heat deterioration of a NOx catalyst (30) in a predetermined time in a case of assuming that a regeneration process is executed for the predetermined time and a progression in the degree of heat deterioration of the NOx catalyst (30) in the predetermined time in a case of assuming that the regeneration process is not executed. The electronic control unit (60) is configured to execute the regeneration process in a case of determining that the difference is less than or equal to the predetermined degree, even when a sulfur poisoning quantity is less than or equal to the permissible upper limit quantity.