There is provided a behavioral model generating device in which a first pattern generator selects behavioral patterns from all the behavioral patterns in behavioral pattern groups by duplicate sampling according to a weighting factor of each group, and adds modification to each pattern to generate first behavioral patterns, a second pattern generator generates device operation patterns from the first behavioral patterns, a power consumption calculator calculates power consumption data based on the device operation patterns, an evaluation selector selects behavioral patterns from the first behavioral patterns by duplicate sampling according to a likelihood of the calculated power consumption data with respect to measured power consumption data, a first updater merges a pair of most similar groups out of all the groups including a group of the selected behavioral patterns and sets a weighting factor of the merged group as a sum of respective weighting factors of the pair.