To generate motion data of a motion in synchronization with a melody of music. As an embodiment of the present invention, when motion pattern data corresponding to a predetermined motion pattern is stored, music data is analyzed to detect a beat of music based on the music data, and the music data is divided into a plurality of bar intervals based on the detected beat, the motion pattern data is allocated to the bar intervals of the music data being divided to generate motion data. In this manner, when the motion data is reproduced together with the music data, the motion pattern can be switched in synchronization with switching of first bar intervals and second bar intervals corresponding to a bar when the music based on music data is expressed in a musical score.