In this paper, we propose an approach that extracts rules of melody that allows human beings to recognize a collection of sound as music. In this approach, sounds created through the process of using random numbers and rules are evaluated by human listeners, and the results acquired from this evaluation are again evaluated to extract the rules. By using this approach, we are able to discover the rule of music that could not be discovered through the approach done in the past (music studies approach and cognitive science approach). The rules used in this rasearch gives constraints, for example, in the sounds' pitch and length, as well as given constraints between groups of sounds.