Chord detection method and apparatus for detecting a chord progression of an input melody

A chord detection method and apparatus for detecting a chord progression for accompaniment of an input melody on a basis of a desired chord applied to a portion of an series of tone pitch sections of the input melody, wherein harmonic tones are extracted from the respective tone pitch sections of the input melody to enumerate each constituent tone of the harmonic tones as a chord candidate for each of the tone pitch sections, and wherein the applied chord and the chord candidate are retrieved in the order of priority with reference to a chord progression suitable for the input melody to determine a chord coincident with the chord progression as each chord of the tone pitch sections.