Abstract: A sign recognizing step of recognizing all signs, including notes, of a music score, a notation estimating step of estimating a drum notation in a drum part of the music score based on information obtained by the step, a musical instrument allocating step of allocating actual tone generating musical instruments to the recognized signs of the drum part according to the drum notation estimated by the step, and a data converting step of converting into a playable and/or displayable music score data format are executed. With this arrangement, the notation of each of the drum scores described by various notations can be recognized so that it can be converted into a playable data format with less operations.