There is provided a musical tone control system capable of controlling the generation of musical tones in a manner reflecting only motion or physical posture suitable for the musical tone generation control when controlling the generation of musical tones reflecting motions of a plurality of users or a plurality of body parts thereof or physical posture thereof. A plurality of motion detecting devices capable of being carried by operators detect motions of the users or operators carrying the devices, and transmit detected motion signals indicative of the detected motions. A receiver device receives the detected motion signals transmitted from the plurality of motion detecting devices. A CPU control extracts at least one detected motion signal satisfying a predetermined condition from the detected motion signals received by the receiver device and controls musical tones to be generated, based on the extracted at least one detected motion signal.