A saxophone is equipped with a supporting system, and the supporting system assists a player in performance on the saxophone; the supporting system includes pressure sensors respectively adhered to the keys of the saxophone, torque motors provided in association with the keys for exerting assisting force on the keys and a controller for adjusting a driving signal to a certain amount correspondingto the pressure; since a conversion table is stored in the controller, the controller looks up the amount of driving current to be adjusted in the conversion table, and supplies the driving signal tothe torque motor, whereby the keys are depressed by the total of finger force and assisting force.