An apparatus and a method for making music data each perform converting an input audio signal indicative of a music piece into a frequency signal indicative of magnitudes of frequency components at predetermined time intervals; extracting frequency components corresponding to tempered tones respectively at the predetermined time intervals from the frequency signal; detecting two chords each formed by a set of three frequency components as the first and second chord candidates, the three frequency components having a large total level of the frequency components corresponding to the extracted tones; and smoothing trains of the detected first and second chord candidates to produce music data.