A motor driving device includes a rectifier, an inverter connected to a DC link on a DC side of the rectifier, a power failure detecting unit for detecting a power failure on the alternating side of the rectifier, an electric storage device connected to the DC link, a charging unit that possesses a voltage boosting function of charging the electric storage device by direct current power at the DC link, a discharging unit that causes direct current power stored in the electric storage device to be discharged to the DC link, and a control unit that causes the charging unit to operate when the power failure detecting unit does not detect a power failure, or before start of motor drive, and causes the discharging unit and the inverter to operate when the power failure detecting unit detects a power failure.