An intercooler system includes an air duct configured to be supplied with outside air, an evaporator, and a heater core of an air-conditioning system being disposed within the air duct. An intercooler is supplied with the outside air from the air duct and configured to cool intake air passing therethrough using the outside air. A valve unit regulates flow of the outside air such that the outside air passes at least one of the evaporator and the heater core and is then supplied to the intercooler. Also, a control unit controls operation of the air-conditioning system and the valve unit.