There is provided a rendition style selector operable by a user to select a desired rendition style from among a plurality of rendition styles associated with a plurality of portions of tones. In response to selecting operation via the selector, a rendition style is determined which is to be applied to each desired portion of a tone. Then, performance information is output which designates a rendition style module corresponding to the determined rendition style. The module defines a waveform characteristic to provide the corresponding rendition style. According to another type of the rendition style selector, a user can collectively select a combination of a plurality of rendition styles associated with different portions of a tone. Thus, a plurality of rendition styles can be designated collectively by one selecting operation. Rendition style suitable for each portion of a tone to be generated may be determined on the basis of a performance event.