An exhaust gas control apparatus for an internal combustion engine, comprising: a catalytic device disposed in an exhaust passage and provided with a NOx storage-reduction catalyst and an oxygen storage agent, the NOx storage-reduction catalyst configured to store peripheral nitrogen oxides under an oxidizing atmosphere and to release stored nitrogen oxides for reduction and purification under a reducing atmosphere, and the oxygen storage agent configured to store peripheral oxygen under the oxidizing atmosphere and release stored oxygen under the reducing atmosphere; a first air-fuel ratio sensor configured to detect an air-fuel ratio of exhaust gas at a time when the exhaust gas flows into the catalytic device; and an electronic control unit configured to execute poisoning recovery control to eliminate sulfur compounds deposited on the catalytic device through temperature-increase processing and elimination processing, the temperature-increase processing being processing to increase a temperature of the catalytic device to a temperature at which the sulfur compounds deposited on the catalytic device is eliminated, and the elimination processing being processing to supply a reducing agent to the catalytic device in a state where the temperature of the catalytic device is the temperature at which the sulfur compounds is eliminated, estimate an oxygen storage amount based on a detection value from the first air-fuel ratio sensor, the oxygen storage amount being an amount of oxygen stored in the catalytic device, determine timing at which an estimation value of the oxygen storage amount becomes equal to or less than a prescribed elimination start determination value after a start of the elimination processing as elimination start timing at which elimination of the sulfur compounds deposited on the catalytic device is started, terminate supply of the reducing agent for the elimination of the sulfur compounds and complete the poisoning recovery control at the termination timing, characterized in that termination timing of the poisoning recovery control is decided based on an amount of the reducing agent supplied to the catalytic device in an elimination period that is a period after the elimination start timing during the elimination processing. a catalytic device disposed in an exhaust passage and provided with a NOx storage-reduction catalyst and an oxygen storage agent, the NOx storage-reduction catalyst configured to store peripheral nitrogen oxides under an oxidizing atmosphere and to release stored nitrogen oxides for reduction and purification under a reducing atmosphere, and the oxygen storage agent configured to store peripheral oxygen under the oxidizing atmosphere and release stored oxygen under the reducing atmosphere; a first air-fuel ratio sensor configured to detect an air-fuel ratio of exhaust gas at a time when the exhaust gas flows into the catalytic device; and an electronic control unit configured to execute poisoning recovery control to eliminate sulfur compounds deposited on the catalytic device through temperature-increase processing and elimination processing, the temperature-increase processing being processing to increase a temperature of the catalytic device to a temperature at which the sulfur compounds deposited on the catalytic device is eliminated, and the elimination processing being processing to supply a reducing agent to the catalytic device in a state where the temperature of the catalytic device is the temperature at which the sulfur compounds is eliminated, estimate an oxygen storage amount based on a detection value from the first air-fuel ratio sensor, the oxygen storage amount being an amount of oxygen stored in the catalytic device, determine timing at which an estimation value of the oxygen storage amount becomes equal to or less than a prescribed elimination start determination value after a start of the elimination processing as elimination start timing at which elimination of the sulfur compounds deposited on the catalytic device is started, execute poisoning recovery control to eliminate sulfur compounds deposited on the catalytic device through temperature-increase processing and elimination processing, the temperature-increase processing being processing to increase a temperature of the catalytic device to a temperature at which the sulfur compounds deposited on the catalytic device is eliminated, and the elimination processing being processing to supply a reducing agent to the catalytic device in a state where the temperature of the catalytic device is the temperature at which the sulfur compounds is eliminated, estimate an oxygen storage amount based on a detection value from the first air-fuel ratio sensor, the oxygen storage amount being an amount of oxygen stored in the catalytic device, determine timing at which an estimation value of the oxygen storage amount becomes equal to or less than a prescribed elimination start determination value after a start of the elimination processing as elimination start timing at which elimination of the sulfur compounds deposited on the catalytic device is started, terminate supply of the reducing agent for the elimination of the sulfur compounds and complete the poisoning recovery control at the termination timing, characterized in that termination timing of the poisoning recovery control is decided based on an amount of the reducing agent supplied to the catalytic device in an elimination period that is a period after the elimination start timing during the elimination processing.