In reviewing past research concerning models of organizational socialization, two schools of model revealed valid. One is called a“stage model, ”the traditional one based on developmental view of individuals, but empirically les validated, and the other is called a“learning model, ”the recent trend based on individuals' information seeking processes with empirically more supportive evidence. Two models seem compatible each other. However, research review implies that for the integration of the two models the former model requires the more solid empiricl validation first. The purpose of this study is to develop a new stage model reflecting on the context of Japanese organizations and to validate it empirically by using Item Response Theory (IRT) techniques. Empirical survey was conducted using 292 young workers as sample. Results revealed that there was less validity in its original four-stage socialization model, but after the modification based on the IRT analysis, the model could prove validity. Implications for future research were made primarily on the adoption of longitudinal survey design, and both intra- and inter-organizational study of organizational socialization process.