PURPOSE: To carry out coolant replenishing always in a suitable amount and eliminate an over-replenishing or a shortage of replenishing of the coolant by calculating a target degree of super-cooling from the outside temperature and automatically stopping replenishing of the coolant for room cooling cycle at the time when the target degree of super-cooling coincides with an actual degree of super-cooling.

CONSTITUTION: In this air conditioner for vehicle an evaporator 8 that constitutes a room cooling cycle 100 is provided in an air conditioning duct and it cools the sucked air. In this case the control of an air conditioner 110 and room cooling cycle 100 is fixed by means 120 to make the load of room cooling constant. And the conditions on high pressure side of the room cooling cycle 100 that operates under the room cooling load that is fixed are detected by means 130, and based on the results of this detection an actual degree of super-cooling is calculated by means 150 and it is compared with an actual degree of super-cooling by means 160 to judge largeness and smallness. And, when actual degree of super-cooling is smaller than the target degree of super-cooling the coolant is replenished by means 170 and when the both coincide the replenishing is stopped by means 180.