Rendition style parameters for realizing various release rendition styles and/or attack rendition styles are stored in a memory. Operation-related time lengths are detected which pertain to turning-on and/or turning-off operation of a pedal operator. Any one of the release rendition style parameters is selected from the memory on the basis of the detected operation-related time length, and the release of a tone is controlled with a characteristic of the selected rendition style parameter. Alternatively, any one of the release or attack rendition style parameters is selected from the memory on the basis of a velocity of the turning-on and/or turning-off operation of the pedal operator detected operation-related time length, and the release or attack of a tone is controlled with a characteristic of the selected rendition style parameter.