PURPOSE: To improve the heat exchanging efficiency by using a nonazeotropically-mixed refrigerant by disposing fans on the downstream side of heat exchangers, said fans delivering the air to one or both sides of a pair of panel type heat exchangers so that the air and refrigerant flowing in the heat exchangers may cross-flow each other.

CONSTITUTION: Under the cooling mode, the room air is blown by a fan 6b upwardly to cool the refrigerant which enters from the upper refrigerant inlet and descends through a room side heat exchanger 5 as it gains the temperature. On the other hand, the outside air is blown downwardly by a fan 6c to heat the refrigerant which enters from the lower refrigerant inlet and rises through an outside heat exchanger 4 as it loses the temperature. Under the heating mode, the reverse cross-flowing heat exchange is performed by the reverse refrigerant circuit and the reverse air flow by fans 6a, 6d. Since the cross- flowing air passage is formed on one or both sides of the heat exchangers 4, 5, a high heat exchanging efficiency can be achieved by using a nonazeotropically-mixed refrigerant.