A rotary driving apparatus includes a motor including a rotor and a stator, a first temperature sensor that detects a stator's temperature and issues a first detection signal including stator's temperature information, a housing accommodating the motor, a cooling medium supply provided in the housing to supply a cooling medium to the motor, an open-close valve provided at a housing's lower portion to open to store the cooling medium inside the housing and close to discharge the cooling medium from the housing, and a controller that predicts a stator's temperature change on the basis of the first detection signal to close, if the stator's temperature is predicted to exceed a motor's operation guarantee temperature, while the motor is driven at an operating point within a motor's time rating region, the open-close valve before starting motor's output restriction, to thereby increase a stored cooling medium amount inside the housing.