We present our framework that efficiently synchronizes dancing motion of a virtual character according to music input. Two modules have been developed to achieve this. A music server analyzes audio input on the fly and extracts information on music such as tempo, time signature, and beat time. A motion client chooses and displays motion clips according to the music information, by time-warping and synchronizing the start time of motion clips with the music beat time. As a preprocessing step, we construct a database of motion clips using captured dancing motion of a dancer. A PCA-based method is presented to easily identify transiting parts from each motion clip.