A refrigerant leakage detection system includes a first controller, and a second controller. The first controller uses a first method to determine the presence or absence of refrigerant leakage from the refrigerant circuit. The second controller uses a second method different from the first method to determine the presence or absence of refrigerant leakage from the refrigerant circuit. The refrigerant leakage detection system determines the presence or absence of refrigerant leakage from the refrigerant circuit on the basis of the determination result of the first controller and the determination result of the second controller. The refrigerant leakage detection system determines that there is a refrigerant leakage in the refrigerant circuit if the first controller determines that there is a refrigerant leakage from the refrigerant circuit and the second controller determines that there is a refrigerant leakage from the refrigerant circuit.