The present invention aims to change contents of an automatic accompaniment in accordance with a pitch range of a key that a user plays. The electronic musical instrument includes operated keys and a processor. The processor acquires the number of operated keys for each pitch range in accordance with the operation of the keyboard and instructs to switch an automatic accompaniment pattern accompaniment sounds to be emitted in accordance with the acquired number of operated keys for each pitch range.

An accompaniment sound generating device includes a specifier, an accompaniment sound generator, and an accompaniment sound outputter. The specifier specifies a plurality of musical performance parts for which accompaniment sounds are generated based on an input musical performance sound. The accompaniment sound generator generates the accompaniment sounds that belong to the plurality of specified musical performance parts for each musical performance sound. The accompaniment sound outputter outputs the accompaniment sounds generated for the plurality of musical performance parts with timing for generating the accompaniment sounds aligned with timing for generating musical performance sounds.

An accompaniment sound generating device includes a specifier, an accompaniment sound generator, and an accompaniment sound outputter. The specifier specifies a plurality of musical performance parts for which accompaniment sounds are generated based on an input musical performance sound. The accompaniment sound generator generates the accompaniment sounds that belong to the plurality of specified musical performance parts for each musical performance sound. The accompaniment sound outputter outputs the accompaniment sounds generated for the plurality of musical performance parts with timing for generating the accompaniment sounds aligned with timing for generating musical performance sounds.