Provided is a technology enabling a temperature of an exhaust gas purifying device to rise more surely by operating an electric heater for a catalyst attached with the electric heater more steadily without exerting an excessive load on a battery. Included are the battery and the electric heater operating upon being supplied with electric power from the battery and heating an occlusion-reduction type NOx catalyst, wherein it is predicted, from a point that a SOx occluded quantity into the occlusion-reduction type NOx catalyst is equal to or larger than S1, that a SOx poisoning recovery process will be executed in near future (S102), and a charging level of the battery is increased (S106) by raising a voltage of power generation of an alternator (S103).