Various arpeggio patterns are provided for an automatic arpeggio performance in an electronic musical apparatus, in which arpeggio notes are sounded in various timbres and appropriate arpeggio types are selected for the respective timbres. For each of a plurality of timbres, plural available arpeggio types are prepared which are appropriate for the timbre, and are assigned to plural arpeggio type selecting buttons, respectively. According to the manipulation of an arpeggio type selecting button, the assigned type is selected and the arpeggio pattern data of the selected arpeggio type are outputted for the successive sounding of the notes as an arpeggio. The assignment of the arpeggio types to the selecting buttons are alterable by the user.