This study examines the historical and long-term recurrence of teacher shortages in modern and contemporary Japan and explores why this problem has not been fundamentally solved. Although research has provided a detailed and complicated background for the recent teacher shortage in Japan, few studies have examined this issue as a historical and continuous problem. The analysis results found four periods when teacher shortage problems occurred. For each period, the study identified three common causes (increasing demand for teachers, economic fluctuations, and reduced incentives) and four common measures (improving incentives, expanding teacher supply routes, deregulation, and improving teacher salaries). In conclusion, this study argues that the teacher shortage problem in modern and contemporary Japan has always been caused by exogenous factors, such as population dynamics and economic changes, because the financial basis for teacher salaries has been too unstable and insufficient to retain teachers and continuously attract teacher candidates. The analysis also suggests that high competition rates for teacher hiring masked the teacher shortage problem, as shown in the reduction in teachers' salaries and incentives. This reduction has also contributed to recent teacher shortages by restricting the number of hires, increasing "non-regular teachers," and decreasing the number of teacher candidates.