A heat pump system for a vehicle which includes a compressor, a condenser, expansion means and an evaporator connected with one another through a refrigerant circulation line, comprising: - an air-conditioning case having a cold air passageway that the evaporator is installed and a warm air passageway that the condenser is installed, partitioned by a partition wall which partitions the inside of the air-conditioning case; - a first blower which is mounted on an inlet of the cold air passageway of the airconditioning case to blow air toward the cold air passageway; - a second blower which is mounted on an inlet of the warm air passageway of the airconditioning case to blow air toward the warm air passageway; and - an intake duct which is communicatingly mounted between the first blower and the second blower to be used commonly for the first and second blowers (130a, 130b) and supplying indoor air and outdoor air to the first blower and the second blower; - wherein the first blower and the second blower are arranged to face each other and to be spaced apart from each other in the width direction of the vehicle, and wherein the intake duct comprises: - an outdoor air inlet for inducing outdoor air; an indoor air inlet for inducing indoor air; - and characterised by a first indoor and outdoor air converting door and a second indoor and outdoor air converting door each of which is mounted between the indoor air inlet and the outdoor air inlet, the first indoor and outdoor air converting door selectively opening the outdoor air inlet and the indoor air inlet for the first blower, the second indoor and outdoor air converting door selectively opening the outdoor air inlet and the indoor air inlet for the second blower. - an air-conditioning case having a cold air passageway that the evaporator is installed and a warm air passageway that the condenser is installed, partitioned by a partition wall which partitions the inside of the air-conditioning case; - a first blower which is mounted on an inlet of the cold air passageway of the airconditioning case to blow air toward the cold air passageway; - a second blower which is mounted on an inlet of the warm air passageway of the airconditioning case to blow air toward the warm air passageway; and - an intake duct which is communicatingly mounted between the first blower and the second blower to be used commonly for the first and second blowers (130a, 130b) and supplying indoor air and outdoor air to the first blower and the second blower; - wherein the first blower and the second blower are arranged to face each other and to be spaced apart from each other in the width direction of the vehicle, and wherein the intake duct comprises: - an outdoor air inlet for inducing outdoor air; an indoor air inlet for inducing indoor air; - and characterised by a first indoor and outdoor air converting door and a second indoor and outdoor air converting door each of which is mounted between the indoor air inlet and the outdoor air inlet, the first indoor and outdoor air converting door selectively opening the outdoor air inlet and the indoor air inlet for the first blower, the second indoor and outdoor air converting door selectively opening the outdoor air inlet and the indoor air inlet for the second blower. - an outdoor air inlet for inducing outdoor air; an indoor air inlet for inducing indoor air; - and characterised by a first indoor and outdoor air converting door and a second indoor and outdoor air converting door each of which is mounted between the indoor air inlet and the outdoor air inlet, the first indoor and outdoor air converting door selectively opening the outdoor air inlet and the indoor air inlet for the first blower, the second indoor and outdoor air converting door selectively opening the outdoor air inlet and the indoor air inlet for the second blower.