To provide a control apparatus and method for a homogeneous charge compression-ignited internal-combustion engine, adapted to reduce combustion noise, as well as fluctuations in torque, during switching from spark-ignited combustion to homogeneous charge compression-ignited combustion. In accordance with information on the operational state of the internal-combustion engine, a combustion mode switching discriminator 21 selects a homogeneous charge compression-ignited combustion mode if the engine is operating under the conditions that allow homogeneous charge compression-ignited combustion. If the engine is operating under the conditions that do not allow homogeneous charge compression-ignited combustion, the combustion mode switching discriminator 21 selects a spark-ignited combustion mode. Immediately after combustion mode switching from spark-ignited combustion to homogeneous charge compression-ignited combustion, a combustion mode switching corrector 28 outputs switching correction quantities with respect to operating quantities for homogeneous charge compression-ignited combustion. The operating quantities for homogeneous charge compression-ignited combustion are adjusted using the switching correction quantities that the combustion mode switching corrector 28 has output with respect to the operating quantities for homogeneous charge compression-ignited combustion immediately after switching to the homogeneous charge compression-ignited combustion mode. New operating quantities obtained from the adjustments are output as control quantities from a combustion mode selector 27.