It is the common knowledge that the modern textile factories, cotton spinning and silk reeling, which led the Japan's industrialization, based their labor foundation on the juvenile female workers. These female workers, however, might have made only a slight impact on the indigenous development based on the household economy as they had withdrawn from factories in their late twenties at the latest and tended to be embedded afterwards in the households of peasants' or urban non-agricultural occupations'. To consider the impact of the industrialization on the indigenous society in Japan, we should pay the special attention to the life courses of the male labor force. The aim of this paper is to give an example of the factory life of the male workers in the middle scale factory, by analyzing the primary source of the firm. The analysis of the archives revealed that the life course as a lifetime factory worker, though the mobility rate between factories was rather high, emerged even in the middle scale factory circa 1910. However, the wage for the worker over the age of twenty was irrelevant to the age, varied just with attendance and the wage level was relatively low in the local labor market. These fact findings indicate that the emergence of the fulltime and lifetime factory workers can not be fully accounted for by the explanation of existing literatures that emphasize the role of the skilled and high wage workers.