1. A frequent pattern extraction apparatus comprising: an acquisition unit configured to acquire time series data for a data operation in user units from a data operation history database; a dividing unit configured to divide the time series data for the data operation into a plurality of data operation sets; a set degree of similarity acquisition unit configured to acquire a set degree of similarity among the plurality of data operation sets; a generation unit configured to generate an abstract data operation set from the plurality of data operation sets using the set degree of similarity; and an extraction unit configured to extract a pattern of a sequence that frequently appears among sequences consisting of the plurality of abstract data operation sets.