An engine and a motor/generator are installed in a vehicle as drive sources. The vehicle is capable of traveling in a condition where the engine is stopped. A monitor varies an indicator in accordance with an operation performed by a driver and a condition of a device installed in the vehicle, and displays the indicator to the driver. When a startup condition based on the operation performed by the driver is satisfied, the device is stopped, and the engine is kept stopped until a predetermined delay time elapses. While the engine remains stopped, variation of the indicator is restricted.