This study aims to analyze the relationship between the instructor’s approach and the students’ thoughts during the process of opera production at Hiroshima University to understand the actual situation of opera production and explore effective ways of teaching and supporting the students. After an overview of the entire opera production process, the analysis focused on the music rehearsal process. The results of the study showed that in engaging in opera production as music learning, there were two approaches based on learner understanding. The first is “a work that promotes complex learning about the various elements that make up an opera.” The interconnectedness of the various elements is a special characteristic of opera as a comprehensive art form. The second is “to further enrich the thinking that is constantly taking place within the learner’s own mind in the performance and production of the work.” The purpose of these efforts was to provide the student the opportunity to learn as an all-rounder who can look at the whole picture, as well as to learn as an expert in a certain field. While these efforts were made by the instructor, the learners were less interested in elements that were not directly related to them, and their learning was biased toward expert learning. In the project-based learning approach at the university, it is necessary for students to learn as all-rounders who generate their own learning from the way others learn. Because of the unique nature of opera, with its complex intertwining of various elements, being aware of others’ learning and one’s own learning is equally important for students. Thus, the study results showed that it is necessary to work not only on the project-based learning characteristic of opera production, but also on the way of learning itself, in order to “construct learning as an all-rounder.”