A pump apparatus includes a motor that rotates a shaft, and a pump that is driven by the shaft, suctions an oil, and delivers the oil to the motor. The pump apparatus includes a first flow channel to suction an oil into the pump through a suction port provided in a pump cover using a negative pressure in the pump, a second flow channel to deliver an oil to the inside of the motor through a delivery port provided in a pump body using pressurization of the pump, a third flow channel provided between a stator and a rotor, a fourth flow channel provided between the stator and a housing, and a fifth flow channel to discharge an oil inside the motor through a discharge port provided in the housing.