Assumed torque Tb is calculated based on an operation state of an engine when there is no abnormality in sensors, the engine is in a warm-up completion state, and a travel mode is a series mode, and actual torque Ta is calculated and friction torque Tf is calculated based on information on an actual amount of electric power generation of a generator. When the friction torque Tf is larger than an upper limit clip value, the upper limit clip value is the friction torque Tf, and when the friction torque Tf is smaller than the lower limit clip value, the lower limit clip value is the friction torque Tf, correction torque Tc is calculated, and an operation of an electronic control instrument of the engine is controlled so as to set the assumed torque Tb to the correction torque Tc.