In a refrigerant leakage warning device for an apparatus having a refrigeration cycle using a flammable refrigerant as a refrigerant, when leakage of the refrigerant occurs, measures how to cope after the leakage of refrigerant occurs are indicated on an indoor unit (1). Therefore, the user can see the indication of the leakage and take the measures to cope with it, and it is possible to hold the damage at a minimum, and to enhance the safety.