An ECU includes: an electronically controlled valve opening degree control unit for increasing the opening degree of an electronically controlled valve, as a temperature of a coolant detected by a water temperature detecting unit is higher; and a gear ratio control unit for changing the gear ratio of an automatic transmission to a gear ratio to be used when a vehicle runs at a slow speed, when the temperature of the coolant detected by the water temperature detecting unit is equal to or higher than a temperature when the electronically controlled valve opening degree control unit sets the opening degree of the electronically controlled valve to be a maximum opening degree, and when an engine speed detected by an engine speed detecting unit is slower than a preset engine speed and a load to an engine detected by a load detecting unit is larger than a preset load.