To discharge air mixed into a circulation path of a cooling device when turning a system off while traveling.

When a braking operation or a steering operation is detected (S120, S130) when a system is turned off (S110) while traveling, first control is executed (S140, S150) such that an electric pump operates over a predetermined time t1 and one phase energization of an inverter is performed, when an element temperature of the inverter exceeds a temperature threshold value ( S160, S170) while the first control is being executed, second control is executed (S180, S190) such that one phase energization of the inverter is stopped and the electric pump operates over a predetermined time t2. That is, mixing of air into the circulation path is decided by observing a rise in element temperature of the inverter while the first control is being executed, and the mixed air is discharged via a reserve tank by executing the second control.