An exhaust gas purification device for an internal combustion engine to be mounted on a vehicle, the device comprising: a catalyst for purifying exhaust gas by reduction of nitrogen oxide included in the exhaust gas discharged from a combustion chamber of the engine, the catalyst having a purification efficiency of the nitrogen oxide varying depending on a temperature (Tcat) of the catalyst; a supply means capable of supplying a reduction agent for the reduction of the nitrogen oxide to the exhaust gas guided to the catalyst and capable of controlling the temperature of the reduction agent depending on an amount of electrical power supplied to the supply means; a control means capable of controlling the temperature of the catalyst depending on an amount of electrical power supplied to the control means; a charge means capable of supplying electrical power to the control means; and a regeneration means capable of regenerating electrical power depending on an operating condition of the vehicle and capable of supplying a regenerated electrical power to at least one of the supply means, the control means and the charge means, the device being characterized by being configured so as: to prohibit controlling the temperature of the catalyst by a prohibition of supplying electrical power from the charge means and the regeneration means to the control means; and to supply the regenerated electrical power to the supply means upon an amount of a remaining battery level of the charge means being larger than a predetermined threshold level or to supply the regenerated electrical power to the charge means upon the amount of a remaining battery level of the charge means being equal to or smaller than the predetermined threshold level, upon a condition of being incapable of supplying the reduction agent in an amount corresponding to the temperature of the catalyst being satisfied, even upon the temperature of the catalyst (Tcat) needing to be controlled. a catalyst for purifying exhaust gas by reduction of nitrogen oxide included in the exhaust gas discharged from a combustion chamber of the engine, the catalyst having a purification efficiency of the nitrogen oxide varying depending on a temperature (Tcat) of the catalyst; a supply means capable of supplying a reduction agent for the reduction of the nitrogen oxide to the exhaust gas guided to the catalyst and capable of controlling the temperature of the reduction agent depending on an amount of electrical power supplied to the supply means; a control means capable of controlling the temperature of the catalyst depending on an amount of electrical power supplied to the control means; a charge means capable of supplying electrical power to the control means; and a regeneration means capable of regenerating electrical power depending on an operating condition of the vehicle and capable of supplying a regenerated electrical power to at least one of the supply means, the control means and the charge means, the device being characterized by being configured so as: to prohibit controlling the temperature of the catalyst by a prohibition of supplying electrical power from the charge means and the regeneration means to the control means; and to supply the regenerated electrical power to the supply means upon an amount of a remaining battery level of the charge means being larger than a predetermined threshold level or to supply the regenerated electrical power to the charge means upon the amount of a remaining battery level of the charge means being equal to or smaller than the predetermined threshold level, upon a condition of being incapable of supplying the reduction agent in an amount corresponding to the temperature of the catalyst being satisfied, even upon the temperature of the catalyst (Tcat) needing to be controlled. to prohibit controlling the temperature of the catalyst by a prohibition of supplying electrical power from the charge means and the regeneration means to the control means; and to supply the regenerated electrical power to the supply means upon an amount of a remaining battery level of the charge means being larger than a predetermined threshold level or to supply the regenerated electrical power to the charge means upon the amount of a remaining battery level of the charge means being equal to or smaller than the predetermined threshold level, upon a condition of being incapable of supplying the reduction agent in an amount corresponding to the temperature of the catalyst being satisfied, even upon the temperature of the catalyst (Tcat) needing to be controlled.