PROBLEM TO BE SOLVED: To provide a sleep state evaluation device for objectively detecting a sleep state of a sleeper (subject) and evaluating quality of sleep of the subject based on the sleep state, with a simple method.SOLUTION: A sleep state evaluation device comprises: sleep state storage means for storing a sleep state which indicates at least one out of three states of a bed-leaving state, a sleep state and an awakening state, as a state of a subject calculation means for, based on the stored sleep state, calculating an on-bed time in the daytime and a sleep time in the daytime and evaluation means for evaluating quality of sleep of the subject based on the on-bed time in the daytime and the sleep time in the daytime.SELECTED DRAWING: Figure 4
