An apparatus and a method for searching for a music piece which includes a storing device for storing first chord progression music data for a plurality of music pieces representing chronological changes in chords in the music pieces. Second chord progression music data representing chronological changes in at least a part of chords in a music piece is produced, the first chord progression music data for the plurality of music pieces stored and the second chord progression music data are compared on the basis of the amount of change in the root of a chord in a chord transition and the attribute of the chord after the transition in order to calculate a similarity for each of the plurality of music pieces, and a search output corresponding to a result of the calculation for each of the plurality of music pieces is produced.