A hybrid electric vehicle comprises an internal combustion engine and an electric motor/generator connected via a first clutch. In response to a system stop request in a vehicle stop state, a rotation speed of the internal combustion engine is decreased to a predetermined rotation speed higher than a predetermined resonance frequency band by a negative torque applied to the internal combustion engine from the electric motor/generator via the first clutch. Then, the disengagement of the first clutch starts. The rotation speed of the engine falls below the predetermined resonance frequency band within a predetermined period from the start of the disengagement. As a consequence, the required period from a stopping operation of the internal combustion engine until actual operation stop thereof in a vehicle stationary state is reduced.