Universal Design for Learning (UDL) is a framework for building flexible learning environments that enable all students to achieve their goals through methods appropriate to each individual. The purpose of this study is to clarify why UDL is not widely applied in Japanese music classes and to explore ways to address this. Under Japan's educational system, the Course of Study (the Curriculum) and compulsory education textbooks are fixed elements that teachers cannot alter. This study focused on third-grade elementary school learning, scrutinizing the Curriculum requirements and textbook content. It attempted to develop and propose teaching methods aligned with the UDL framework across four activity domains: singing, instrumental performance, music creation, and appreciation. The results showed this was particularly challenging in the instrumental domain. The primary reason is that the textbook exclusively treats the keyboard-harmonica and the recorder as melody instruments. Although playing these instruments requires complex combinations of blowing, fingering, and tonguing, students in third grade and above are expected to play them while reading sheet music. According to a report by the Ministry of Health, Labour and Welfare (2022), 5-6% of students may have developmental coordination disorder. The current estimate is that the proportion of school-age children with developmental dyslexia exceeds 5%. These students may have difficulties with fine motor skills and eye-hand coordination. An author-conducted survey of 127 schools (2016) found that approximately 19% of students had difficulty playing while reading sheet music. Furthermore, recent psychological research (Yamazawa. et al. 2024) suggests that approximately 4.6% of students may experience auditory hypersensitivity. Such students may feel stressed when practicing individually in the classroom. To promote UDL, teachers must shift their mindset so that all students can find learning methods suited to them. Keeping the Curriculum goal of “cultivating qualities and abilities for rich engagement with sound and music” in mind, researchers and teachers should prepare options beyond textbook content. For example, options could include offering easier-to-operate electronic keyboards or Figurenote to reduce the burden of sight-reading. The Curriculum is by no means rigid and encourages diverse learning approaches. The issue of sound itself becoming a stressor remains a major problem in music education, making it difficult to achieve individually optimized learning environments. Cooperation among schools, parents, teachers, and researchers is crucial to enable options like using earmuffs or practicing in separate spaces so that students with auditory hypersensitivity can learn comfortably.