A wakefulness maintaining apparatus includes an event detecting part, a drowsiness level determining part, a threshold setting part, and a stimulus supplying part. The event detecting part detects an event related to a drowsiness of a person. The drowsiness level determining part determines a drowsiness level that changes in accordance with a strength of the drowsiness. The threshold setting part sets a threshold value to divide the drowsiness level into a first level range and a second level range in such a manner that the first level range is equal to or lower than the threshold value and the second level range is higher than the threshold value. The stimulus supplying part supplies a stimulus having an awaking effect to the person when the drowsiness level is in the second level range and the event is detected.
Wakefulness maintaining apparatus and method of maintaining wakefulness