In most Japanese companies, regular employees work under a lifetime employment system and a seniority-based pay system. Under such conditions of no contingent money payments, we can accurately observe the phenomena associated with intrinsic motivation. Therefore, we conducted Survey X, an exhaustive survey for all employees of Company X carried out once a fiscal year, during the fiscal years 2004–2013. Using the total 13,019 employees' data of Survey X, we test a version of Deci's (1975) hypothesis that if a person's feeling of self-determination is enhanced, his or her job satisfaction will increase. As a result, there is a strong linear relationship between the job satisfaction ratio and the degree of self-determination. However, occupation and rank tend to determine the band of fluctuation with respect to the degree of self-determination. This indicates a strong likelihood that there is a spurious correlation between a degree of self-determination and a job satisfaction ratio.