A control apparatus for a gas turbine system for driving a power generator through rotation of a turbine , the control apparatus comprising: a sensing unit configured to measure a turbine inlet temperature indicating a temperature of combustion gas introduced into the turbine of the gas turbine system and to measure an exhaust gas temperature indicating a temperature of exhaust gas discharged from the turbine ; and a compressed air control unit configured to control an air supplying means of the gas turbine system to adjust the amount of compressed air supplied to the turbine , based on the measured turbine inlet temperature and the measured exhaust gas temperature; wherein if the turbine inlet temperature cannot be measured: the sensing unit is configured to measure a revolutions-per-minute (RPM) value of a rotor installed in the turbine and to measure an exhaust gas temperature indicating a temperature of exhaust gas discharged from the turbine ; and the compressed air control unit is configured to control the air supplying means to adjust the amount of compressed air supplied to the turbine , based on the measured RPM value of the rotor and the measured exhaust gas temperature; and wherein the compressed air control unit is further configured to: control the air supplying means to supply a first amount of compressed air, when the exhaust gas temperature is less than a preset threshold value, and control the air supplying means to additionally supply a third amount of compressed air, when the exhaust gas temperature reaches the preset threshold value and the RPM value of the rotor is less than or equal to an inflection point RPM value, and wherein the inflection point RPM value indicates the RPM value of the rotor when the exhaust gas temperature starts to change from the preset threshold value to a value lower than the preset threshold value. a sensing unit configured to measure a turbine inlet temperature indicating a temperature of combustion gas introduced into the turbine of the gas turbine system and to measure an exhaust gas temperature indicating a temperature of exhaust gas discharged from the turbine ; and a compressed air control unit configured to control an air supplying means of the gas turbine system to adjust the amount of compressed air supplied to the turbine , based on the measured turbine inlet temperature and the measured exhaust gas temperature; the sensing unit is configured to measure a revolutions-per-minute (RPM) value of a rotor installed in the turbine and to measure an exhaust gas temperature indicating a temperature of exhaust gas discharged from the turbine ; and the compressed air control unit is configured to control the air supplying means to adjust the amount of compressed air supplied to the turbine , based on the measured RPM value of the rotor and the measured exhaust gas temperature; and wherein the compressed air control unit is further configured to: control the air supplying means to supply a first amount of compressed air, when the exhaust gas temperature is less than a preset threshold value, and control the air supplying means to additionally supply a third amount of compressed air, when the exhaust gas temperature reaches the preset threshold value and the RPM value of the rotor is less than or equal to an inflection point RPM value, and control the air supplying means to supply a first amount of compressed air, when the exhaust gas temperature is less than a preset threshold value, and control the air supplying means to additionally supply a third amount of compressed air, when the exhaust gas temperature reaches the preset threshold value and the RPM value of the rotor is less than or equal to an inflection point RPM value, and wherein the inflection point RPM value indicates the RPM value of the rotor when the exhaust gas temperature starts to change from the preset threshold value to a value lower than the preset threshold value. <EOS>