PURPOSE: To enable the device to perform heat exchange ventilation/space heating, normal ventilation/space heating concurrently performing air supply and vent, as well as recirculation space heating by incorporating a heater in an air duct connecting the room side air outlet and a feed air fan.

CONSTITUTION: When the heat exchange ventilation is performed, dampers 9, 10 are closed to direct the air flowing through the heat exchanging element 1 as vent air A1 and feed air B1. As a result, the room air 36a enters from the upper left room air inlet and is vented through the heat exchanging element 1 and an air vent fan 6 to the outside out of the lower left air outlet. Similarly, the outside air 37a is taken in from the lower right air inlet and is supplied into the room through the heat exchanging element 1 and a fan 7 out of the upper right air outlet. By activating a heater 8, the air can be supplied after being heated even if the feed air temperature is low during the winter season. Therefore, a heat exchange ventilation/space heating can be performed. Thus, the ventilation and space heating can be performed even if the outside temperature is low.