A cooling apparatus for an autonomous driving controller may include, a chiller fluidically connected to an air-conditioning system through a refrigerant connection line so that a refrigerant circulating in the air-conditioning system provided in the vehicle is introduced into the chiller; a reservoir tank storing a coolant, and fluidically connected to the chiller; and a water pump mounted between the reservoir tank and the autonomous driving controller; wherein coolant pipes connected to the water pump and the chiller may be connected to the autonomous driving controller respectively.