A total heat exchange device includes: a fan for the exhaust air path which directs air from an indoor exhaust port to an outdoor discharge port through an exhaust air path; another fan for intake air path which directs air from an outdoor suction port to an indoor intake port through an intake air path; and a heat exchange element for exchanging heat between air passing through the exhaust air path and air passing through the intake air path. Also included is a temperature detector for detecting an outdoor temperature and a controller configured to perform a heat exchange mode in which heat is exchanged between air passing through the exhaust air path and air passing through the intake air path or a defrosting mode in which frost on the heat exchange element is thawed, in accordance with the outdoor temperature detected by the temperature detector.