When there is an extremely low ambient temperature, an electronic control unit controls operation of a circulation path for coolant water in such a manner that, after starting of an engine, the coolant water is supplied from the engine first to a throttle valve and an EGR valve and then to an oil warmer for a transmission. This solves a failure problem in the throttle valve and the EGR valve caused by frost formation at an early stage. As a result, desired operating performance of the vehicle is quickly ensured and heat management in the vehicle is carried out in a desired manner when there is an extremely low ambient temperature.