A control device that operates a plurality of actuators (2, 4, 6, 8) to control an internal combustion engine in which a combustion air-fuel ratio in the vicinity of an ignition plug differs from an overall air-fuel ratio in a cylinder, the control device comprising: target value setup means which uses three physical quantities, namely, an output torque, an efficiency, which is a dimensionless parameter that is equivalent to conversion efficiency of thermal energy to the output torque, and an overall air-fuel ratio, as controlled variables for the internal combustion engine, and sets a target value for each controlled variable by determining the most satisfactory numerical values of the three physical quantities in consideration of a priority of performance requirements of the internal combustion engine; operation amount setup means which sets three operation amounts, namely, a throttle opening, an ignition timing, and a fuel injection amount, and a fourth operation amount for adjusting the air-fuel ratio distribution in the cylinder; and operation amount output means which outputs each of the set four operation amounts to the corresponding actuators (2, 4, 6, 8) to be operated, characterized in that: the operation amount setup means comprises: means which converts the target values for each of the three controlled variables into the three operational amounts, namely, the throttle opening, the ignition timing, and the fuel injection amount; means which obtains a target combustion air-fuel ratio from the target torque, the target overall air-fuel ratio, the ignition timing and the throttle opening based on torque-ignition timing characteristics in which an intake air amount calculated from the throttle opening, the overall air-fuel ratio and the combustion air-fuel ratio are defined as parameters; and means which obtains the fourth operation amount based on the target combustion air-fuel ratio and the fuel injection amount. target value setup means which uses three physical quantities, namely, an output torque, an efficiency, which is a dimensionless parameter that is equivalent to conversion efficiency of thermal energy to the output torque, and an overall air-fuel ratio, as controlled variables for the internal combustion engine, and sets a target value for each controlled variable by determining the most satisfactory numerical values of the three physical quantities in consideration of a priority of performance requirements of the internal combustion engine; operation amount setup means which sets three operation amounts, namely, a throttle opening, an ignition timing, and a fuel injection amount, and a fourth operation amount for adjusting the air-fuel ratio distribution in the cylinder; and operation amount output means which outputs each of the set four operation amounts to the corresponding actuators (2, 4, 6, 8) to be operated, characterized in that: the operation amount setup means comprises: means which converts the target values for each of the three controlled variables into the three operational amounts, namely, the throttle opening, the ignition timing, and the fuel injection amount; means which obtains a target combustion air-fuel ratio from the target torque, the target overall air-fuel ratio, the ignition timing and the throttle opening based on torque-ignition timing characteristics in which an intake air amount calculated from the throttle opening, the overall air-fuel ratio and the combustion air-fuel ratio are defined as parameters; and means which obtains the fourth operation amount based on the target combustion air-fuel ratio and the fuel injection amount. means which converts the target values for each of the three controlled variables into the three operational amounts, namely, the throttle opening, the ignition timing, and the fuel injection amount; means which obtains a target combustion air-fuel ratio from the target torque, the target overall air-fuel ratio, the ignition timing and the throttle opening based on torque-ignition timing characteristics in which an intake air amount calculated from the throttle opening, the overall air-fuel ratio and the combustion air-fuel ratio are defined as parameters; and means which obtains the fourth operation amount based on the target combustion air-fuel ratio and the fuel injection amount.