A control apparatus for an internal combustion engine having a generator configured to generate electric power by using an output of the internal combustion engine and a electricity storage apparatus configured to store the electric power generated by the generator, the control apparatus for the internal combustion engine comprising: a temperature acquiring unit which is configured to acquire a temperature of the internal combustion engine; a throttle valve driving unit which is configured to drive a throttle valve to open/close the throttle valve provided in an intake passage of the internal combustion engine; a throttle valve opening degree control unit which is configured to control the throttle valve driving unit so that if a variation amount of decrease in output of the internal combustion engine exceeds a predetermined variation amount when the output of the internal combustion engine is smaller than a predetermined output in a non-warm-up state in which the temperature of the internal combustion engine acquired by the temperature acquiring unit is equal to or lower than a predetermined temperature, an opening degree of the throttle valve becomes a predetermined increased opening degree which is increased as compared with a standard opening degree as an opening degree of the throttle valve to be provided if the variation amount does not exceed the predetermined variation amount; and a electricity storage control unit which is configured to store the electric power generated by the generator in the electricity storage apparatus corresponding to increase in output of the internal combustion engine based on an amount of increase from the standard opening degree to the predetermined increased opening degree brought about by the throttle valve opening degree control unit. a temperature acquiring unit which is configured to acquire a temperature of the internal combustion engine; a throttle valve driving unit which is configured to drive a throttle valve to open/close the throttle valve provided in an intake passage of the internal combustion engine; a throttle valve opening degree control unit which is configured to control the throttle valve driving unit so that if a variation amount of decrease in output of the internal combustion engine exceeds a predetermined variation amount when the output of the internal combustion engine is smaller than a predetermined output in a non-warm-up state in which the temperature of the internal combustion engine acquired by the temperature acquiring unit is equal to or lower than a predetermined temperature, an opening degree of the throttle valve becomes a predetermined increased opening degree which is increased as compared with a standard opening degree as an opening degree of the throttle valve to be provided if the variation amount does not exceed the predetermined variation amount; and a electricity storage control unit which is configured to store the electric power generated by the generator in the electricity storage apparatus corresponding to increase in output of the internal combustion engine based on an amount of increase from the standard opening degree to the predetermined increased opening degree brought about by the throttle valve opening degree control unit.