An automatic musical composition classification device and method that allow a plurality of musical compositions to be automatically classified based on the melody similarity. Chord progression pattern data representing a chord progression sequence for each of the plurality of musical compositions are saved, chord-progression variation characteristic amounts are extracted for each of the plurality of musical compositions in accordance with the chord progression pattern data, and the plurality of musical compositions are grouped in accordance with the chord progression sequence represented by the chord progression pattern data of each of the plurality of musical compositions and with the chord-progression variation characteristic amounts.