A representative feature extraction system which selects a representative feature from an input data group includes: occurrence distribution memory means for memorizing an occurrence distribution with respect to feature quantities assumed to be input; evaluation value calculation means for calculating, with respect to each of data items in the data group, the sum of distances to the other data items included in the data group based on the occurrence distribution, to determine an evaluation value for the data item; and data selecting means for selecting the data item having the smallest evaluation value as a representative feature of the data group.