A controller for an internal-combustion engine, wherein the requirements for various functions of the internal-combustion engine can be satisfied properly by reflecting such requirements accurately in the operation of each actuator. A requirement output section (10) represents each of the requirements for various functions of the internal-combustion engine using any values of torque, efficiency or air-fuel ratio to provide such requirements as an output. A torque arbitration section (22) aggregates the requirement values represented by the torque among a plurality of requirement values output from the requirement output section (10) to conduct arbitration into a single torque requirement value. An efficiency arbitration section (24) aggregates the requirement values represented by the efficiency to conduct arbitration into a single efficiency requirement value. An air-fuel ratio arbitration section (26) aggregates the requirement values represented by the air-fuel ratio to conduct arbitration into a single air-fuel ratio requirement value. A control amount computation section (30) computes the control amount for each of actuators (42), (44) and (46) depending on the torque requirement value, efficiency requirement value and air-fuel ratio requirement value that are output from each of arbitration sections (22), (24) and (26).