An apparatus is to assist an unskilled player in playing a musical instrument by detecting the quantity of the player's manipulation against the instrument, modifying the detected manipulation quantity with reference to a recommended manipulation to a degree according to a given assistance coefficient, and actuating the instrument with the modified manipulation quantity. For a brass instrument, the apparatus comprises an embouchure sensor and a breath pressure sensor to detect the embouchure and the breath pressure of the player as he/she plays the brass instrument. The detected embouchure and breath pressure are then modified with reference to a recommended embouchure and breath pressure weighted by a given assistance coefficient. The apparatus actuates the brass instrument based on the modified embouchure and breath pressure.