Based on acceleration-sensor values from a three-dimensional acceleration sensor 23, CPU 21 of a performance apparatus 11 determines a timing at which a musical tone is generated. Further, based on the acceleration-sensor values of the acceleration sensor 23 given at a predetermined timing, for example, at a time when a player starts swinging of the performance apparatus 11, a roll angle of the performance apparatus 11 rotating about an axis in its longitudinal direction is calculated. A timbre of musical tones to be generated is determined based on the calculated roll angle.