Abstract: The present invention provides a new sleep analysis technique with which sleep analysis with relatively high reliability can be simply and speedily performed by using sleeping depth data. An appearance ratio conversion processing portion reads sleeping depth data (qualitative variable) stored in a RAM to calculate a movement appearance ratio n-M.A.R. (quantitative variable) meeting a relation of sleeping depth=2 (deep sleep: SWS). Then, an evaluation result calculation processing portion reads the calculated movement appearance ratio data (quantitative variable) from the RAM, and processes the calculated movement appearance ratio data in accordance with an evaluation rule in an evaluation rule storage portion to calculate an evaluation score for the evaluation factor concerned. When the evaluation factor is “rapidity of falling asleep” for example, a time period from a point when a person goes to bed to a point when the movement appearance ratio n-M.A.R.