As the fluidity of labor market in Japan become higher, the proportion of mid-career recruitment has increased. However, human resource management of Japanese companies is still based on planned development of new graduate employees. Therefore, mid-career employees may relatively fall into slackened growth in the long run. This paper, at first, empirically demonstrated that there is really a difference in growth between new graduate employees and midcareer employees. Then, to explore the elements that are required for midcareer employees to keep growing through continuous work, intensive interview was conducted. The result shows that there is a significant difference between new graduate employees and mid-career employees in in-house competition consciousness. Moreover, it is revealed that the network with same joined-year employees served as an information channel, and lack of such network caused difficulty in inter-departments communication. Based on these findings, to promote more effective use of mid-career employees, this paper proposes to introduce measures to allow more internal competition, and to enable in-house network creation for mid-career employees that serves as weak ties.