PROBLEM TO BE SOLVED: To stabilize sleep stage estimation accuracy becoming different according to the change of a daily body condition so as to enable estimation with high accuracy.SOLUTION: A sleep stage estimating device includes: a filter allowing a given frequency band to penetrate specific frequency band extracting means for extracting data of the frequency band using the filter from organism data acquired by an organism data acquisition part and sleep stage determining means for determining a sleep stage in an organism data acquisition time point on the basis of the extracted data. The filter comprises using a filter which is produced by DcGA, using a data set as an aggregate of a plurality of filter individuals, comprising a plurality of filters allowing various frequency bands to penetrate, and an evaluation value to an outcome determining a sleep stage on the basis of data extracted from past organism data using the filters.
