Is musical training required to acquire knowledge of harmonic processing? Growing body of studies has shown that non-musicians implicitly learn knowledge of harmonic processing just by simple exposure to music. This study reviews priming experiments designed to investigate non-musicians’ implicit knowledge of harmonic processing and introduce electrophysiological experiments to show what are neurobiological resources in the brain for harmonic processing. Priming experiments indicate that, when people listen to harmonic sequences, harmonically related chords are more quickly and correctly processed than harmonically unrelated targets because harmonic priming helps the effective process of harmonically related chords. Harmonic priming is indexed by brain evoked potentials like ERAN(early right anterior negativity) and N5, which is evoked only by passive listening. It suggests that harmonic priming is very automatic and implicit processing in the pre- attentive level.