This study aimed to distinguish the characteristics of the guidance provided by tone bars in the Montessori Method through an examination of documents written by A. M. Maccheroni. Throughout her life, Maccheroni collaborated with M. Montessori. Maccheroni contributed to the development of music education in the Montessori Method. Tone bars and bells are educational materials employed in the Montessori Method, and the use of tone bars was introduced by Maccheroni. This study found that by using tone bars, it was Maccheroni’s intention that children should acquire specialized knowledge of music, including writing and reading music and musical theory. Furthermore, the guidance provided by the tone bars follows a system like that with the guidance provided by bells. However, there is a difference between them: the guidance provided by tone bars relates to teacher-centered education, whereas the guidance provided by bells conforms to child-centered education.