A plurality of play style dependence tone colors belonging to one kind of musical instrument tone color but being different from one another in terms of play styles are respectively assigned to different values of velocity and note number. For example, play style dependence tone colors such as open soft and open middle of a steel guitar are assigned to tone pitch ranges C2 to B5, and the play style dependence tone colors are respectively assigned to different velocity values. Play style dependence tone colors such as strumming and fret noise of a steel guitar are assigned to tone pitch ranges C6 to G8, and the play style dependence tone colors are respectively assigned to different note number values. By setting the note number and velocity values in note-on event data in various ways, musical tone signals of various play style dependence tone colors are generated even if the program change and bank select data are not changed. This provides shorter processing time needed for switching among tone colors of different play styles, and also the work of editing the performance data or the like including the switching of the tone colors can be performed easily and accurately.