Coal extraction was an influential economic activity in interwar Japan. Initially, coal mines employed both males and females as the workforce in the pits. However, the innovation of labor-saving technologies and the renewal of traditional extraction methodology induced institutional change. This was manifested by the revision of labor regulations affecting female miners in the early 1930s. This dramatically changed the mining workplace, making skilled males the principal miners engaged in underground work. This paper investigates the impact of coal mining on regional growth and assesses how the institutional changes induced by the amended labor regulations affected its processes. By linking the mines' location information with both registration and census-based statistics, it was found that coal mines led to remarkable population growth. Fertility rate increased following the implementation of labor regulations that required female miners to leave the workforce and start families. The regulations prohibited female miners from risky underground work. This reduction in occupational hazard also improved early-life mortality via the mortality selection mechanism in utero.