A musical-tone-control apparatus having finger sensors that detect the bending of each finger and produce on/off signals in response to the bending. One group of outputs of the finger sensors is converted into keycodes that control tone pitches by the use of converting rules, and the other group of the outputs thereof is also used for changing the ranges of the tone pitches. Hence, musical tones controlled by finger motions of a performer are generated. Moreover, the converting rules can be altered by a modification-control means so that keycode-conversion rules can be varied. Thus, conversion rules appropriate for generating tones which occur frequently and are easy to produce for an individual, can be set for each musical piece. Furthermore, grouping the outputs of finger sensors makes it possible for a performer to achieve a variety of control of musical tones.