Peculiarities of the development of music performance skills in the school age discussed in the article and an experimental study of the role of cultural tools in that development suggest that this process is governed by the general regularities of the formation of higher psychological functions. In children of primary and middle school ages performance skills develop through the use of exterior cultural tools while high school children mainly rely on interior tools. It has been proved that an adequate exterior tool for developing a capacity for creating a performance image at early stages of instruction is a fairy tale composed by children. The music pieces to be mastered are incorporated in the tale. An objective criterion for this tool is cognitive complexity of the tale which is directly proportional to its productivity.