A sleep evaluation device (1) has a sensor unit (2) that constantly detects body movements of a human subject on bedding, and has a determiner that, based on results of detection, determines a sleep state and an aroused state of the human subject. The determiner quantifies results of detection of the sensor unit into N number of body movement data (where, N is a positive integral number satisfying N ≥ 2) and obtains, based on G number of standard deviations for each of G groups (in which G is an integral number satisfying 2 ≤ G N ) dividing N number of body movement data and for each body movement data and gs ( gs G ) number of standard deviations selected therefrom, L number of average value of standard deviations (where L is an integral number satisfying 2 ≤ L ≤ G ). The determination of a sleep state and an aroused state of the human subject is based on G number of standard deviations and L number of average values of standard deviations.