An accompaniment data generating apparatus has a storage device 15 for storing a set of phrase waveform data having a plurality of constituent notes which form a chord, and a CPU 9. The CPU 9 carries out a process for separating the set of phrase waveform data having a plurality of constituent notes which form a chord into a plurality of sets of phrase waveform data each having different one of the chord constituent notes, an obtaining process for obtaining chord information by which a chord type and a chord root are identified, and a chord note phrase generating process for pitch-shifting one or more of the separated phrase waveform data sets in accordance with chord type and combining the separated phrase waveform data sets including the pitch-shifted phrase waveform data to generate waveform data indicative of a chord note phrase as accompaniment data.