PURPOSE: To prevent a drop in heating capacity of an air conditioner when the outside temperature is low by connecting a heat source air carrying duct to an outlet port of a solar air collector such that the air heated in the collector is carried to an outdoor unit through the carrying duct.

CONSTITUTION: Where the temperature of air heated by the solar heat is below 30°C because of a sunlight deficiency in cloudy winter days, and therefore, the space heating cannot be performed by a solar air collector 1, obliging the space heating to be performed by an air conditioner, air is introduced into the solar air collector 1 by a fan 12 in attic. The air heated in the solar air collector 1 is delivered from the rear of an outdoor unit 2 through a heat source air carrying duct 3 to raise the temperature around the outdoor unit 2. As a result, heat is collected from the warm air by the outdoor unit 2, permitting a high heating efficiency without causing a reduction in the heating capacity of the air conditioner.