A combustion control device for an engine capable of operation over a wide range and in which the NOx discharged amount is small is provided, as well as a combustion method for a homogeneous lean air/fuel mixture. The combustion method for a homogeneous lean air/fuel mixture of the present invention forms a homogeneous lean air/fuel mixture inside of the cylinder of the engine, and then causes this homogeneous lean air/fuel mixture to combust by way of spark ignition. A temperature at which a steep rise in a laminar burning velocity occurs when changing a cylinder temperature under a pressure condition corresponding to compression top dead center is defined as an inflection-point temperature. With the combustion method of the present invention, the cylinder temperature at compression top dead center inside of the cylinder is raised to higher than the inflection-point temperature upon combusting the homogeneous lean air/fuel mixture.