(57) ABSTRACT A sleep state measuring apparatus includes an autonomic nerve index
obtaining unit that obtains a user's autonomic nerve index; and a sleep periodicity index
calculating unit that calculates a sleep periodicity index based on a temporal change of the
autonomic nerve index and a change in a user's sleeping cycle, wherein the sleep
periodicity index indicates whether the user is sleeping or not according to a user's ideal
sleeping cycle as an index, or a dominance index calculating unit that calculates a …