A rolling stock ventilator including an air supply fan, an exhaust fan an inverter for changing air feed characteristics of the air supply fan and the exhaust fan. Flow path resistance changers, a tunnel detector to detect the presence of a tunnel, and a car internal pressure detector are also provided. A controller provides signals to the inverters and the flow path resistance changers with the signals representing a control command to change the operation frequency of the air supply fan and the exhaust fan in accordance with the result of a detection by the tunnel detector and the car internal pressure detector and also provides a control command to change the air feed resistance of the flow path resistance changers.