A high disease burden of mental disorders has been noted worldwide, including Japan. It is important to monitor mental disorder prevalence trends and the use of mental health services over time using epidemiological data and to plan appropriate policies and measures that consider mental health in each country. This review outlines the prevalence trends of common mental disorders (CMD) and the use of mental health services in Japan from the 2000s to the 2010s and compares them with those in other countries. This review clarifies that the prevalence of CMD in Japan has been relatively stable in the past decade. The 12-month prevalence of mental health service use has increased about 1.2 times to 1.6 times in the past 10–15 years. Thus, it is very likely that the rise in mental health service use contributes to increased patient numbers. Regarding cross-national comparison, the prevalence rate of CMD in Japan is much lower compared to rates in the USA and Europe. The 12-month prevalence of mental health service use was also lower in Japan compared to prevalence rates in other high-income countries. Mental health epidemiology has clarified that the prevalence of CMD worldwide has remained unchanged, even though mental health service use has increased in high-income countries. Thus, the gap in treatment quality and prevention should be addressed in the future.