PURPOSE: To achieve a discharging of odor generated in an odor generation space locally outdoors from the odor generation space by stopping an exhaust fan to make the amount of air supplied larger than the amount of air to be exhausted relatively when a heat exchange ventilator performs a supercharge mode operation interlocking the operation of a ventilation fan.

CONSTITUTION: A ventilation fan 20 is arranged in an odor generation space Y1 to discharge odor generated in the odor generation space Y1 outdoors and a heat exchange ventilator 10 performs a supercharge mode operation to make the amount of air supplied of an air fan 101 larger than the amount of the air to be exhausted of an exhaust fan 102 relatively interlocking with the operation of the ventilation fan. In the supercharge mode operation, the exhaust fan 102 is stopped. As a result, the flow of air in a main life space X1 is confined to one system of the flow alone toward the odor generation space Y1 from the main life space X1. This enables discharging of odor generated in the odor generation space Y1 locally from the odor generation space Y1.