Parameters in the internal combustion engines are variable depending on the operating points. Therefore, it is necessary to compensate for the uncertainties. Form this point of view, this paper gives a controller design method and a robust stability condition by LMI approach for engine torque control which satisfies the gives H$infty$ control performance in the presence of physical parameter perturbations. To the end, the robustness of the system in the presence of perturbation is guaranteed in the all engine operating regions. Its effectiveness is demonstrated by simulation.