In vehicle operation under cruise mode, the battery, which is in a low temperature state, is caused to rise in temperature at an early stage, and the assistance amount and the regeneration power generation amount by means of the motor are caused to increase. During vehicle operation in cruise mode, in the case in which one or the other of the battery temperature and the engine water temperature have failed to reach a predetermined temperature, the cruise power generation amount is raised to a predetermined level, and charging of the battery is continued until both the battery temperature and the engine water temperature have reached predetermined temperatures. When a determination has been made that there is no further room in the battery to accept further charge, power generation and assistance is conducted by the motor so as to cancel periodic fluctuations in the drive force of the engine, and vibration damping control is conducted for suppressing vibrations generated by the engine in accordance with the fluctuations in the drive force of the engine.