An arpeggio playing apparatus comprises an arpeggio pattern storing device, an arpeggio pattern readout device and an arpeggio tone processing device. The arpeggio pattern storing device stores at least one arpeggio pattern pair including a regular version pattern and an accentuated version pattern for automatic arpeggio performances. When there comes a key-on event representing an arpeggio designation and a key-on velocity, the arpeggio pattern readout device reads out, from the arpeggio pattern storing device, the regular version pattern when the detected velocity is less than a predetermined threshold value, and the accentuated version pattern when the detected velocity is not less than the predetermined threshold value. The arpeggio tone processing device automatically plays arpeggio based on the arpeggio designation by the key-on event and according to the arpeggio patterns of the read-out versions.