This paper examines the rationalization tendency that has appeared in modern Korean traditional music pitch-related theory since the 20th century within Max Weber's concept. First, with the tendency to emphasize intelligence and objectivity rather than emotion or subjectivity in music, an example would be a theory that explains ‘Jo’ through quantified concepts such as pitch relationships. This is in line with the rationalization and modern mentality that seeks to grasp the world as calculable. Second, there is a pitch-related theory system that is formed as a individual notes disconnected from external qualitative things, like money or bureaucrats discussed in Weber's sociology. Third is the functionalization aspect given here. While discussing modern bureaucracy, Weber viewed function-centered systemization as an advanced form of rationalization.. In music, he also understands the functional differentiation of notes as a process of rationalization. In modern Korean traditional music pitch-related theory, individual notes such as tuning notes, central notes, keynotes, and ending notes have become major topics. Lastly, like Max Weber’s “iron cage”, we can hear the tendency for pitch-related theory, which has been inductively analyzed and categorized from music practice, to influence musical behavior with its own laws. In addition, to understand this, this paper mentioned the de-rationalization trend that appears in recent studies. Examples include research on the variability of notes, its relationship with qualitative aspects outside the sound, and dynamic scale theory.