Abstract: 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 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 fiscal years 2004-2013. Using 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 job satisfaction ratio and degree of self-determination. However, occupation and rank tend to determine band of fluctuation with respect to 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.Keywords: self-determination, intrinsic motivation, job satisfaction, white-collar workers1.1. IntroductionAccording to expectancy theory, most popular and most sophisticated theory on work motivation, force to perform an act should be formulated in a similar manner to expected utility theory in economics. The present well-known expectancy theory of work was completed by Vroom (1964), while prototype of similar model dates back to 1930s. Vroom's theory is fundamentally based on assumption that a person is calculating and rational. Thus, motivating that person to engage in a particular act is formulated as like dangling a carrot in front of a horse's nose. However, based on results of a comprehensive survey of literature, Vroom suggests that may be an as well as a means to attainment of an end and that individuals may derive satisfaction from effective and dissatisfaction from ineffective performance, regardless of externally mediated consequences of performance (Vroom, 1964, p. 267).In fact, although job and job satisfaction have stuck together, external rewards such as money have an overwhelming impact and separate job satisfaction from job performance. Thus, monetary rewards compel satisfaction to be driven by rewards. In other words, monetary rewards have a separating effect: job ->* monetary rewards ->* job satisfaction. If workers working solely for money receive no monetary rewards, lose their satisfaction and their willingness to work (Takahashi, 2004). On this point, Deci (1975) states that external rewards have a greater salience and impact, and they can 'co-opt' intrinsic motivation (Deci, 1975, p. 139). Actually, there is no additional relationship between intrinsic and by external rewards; many experimental studies prove that in many cases, external rewards reduce intrinsic (Deci, 1975, chap. 5).According to Deci (1975), intrinsically motivated are ones for which there is no apparent reward except activity itself (Deci, 1975, p. 23). In contrast to expectancy theory which, supposes that are done as means to external rewards, intrinsically motivated are ends in themselves rather than means to an end; the person is deriving enjoyment from activities (Deci, 1975, p. 23).Deci (1975) defines intrinsically motivated as behaviors which a person engages in to feel competent and self-determining (Deci, 1975, p. 61). The concept of competence here was originally used by White (1959) in a much broader meaning than its everyday usage. White refers to it as ability of an organism to react effectively with its environment. The of visual exploration, grasping, crawling, walking, thinking, exploring novel objects and places, and producing effective changes in environment are supposed to have a common biological significance: all form part of process whereby animal or child learns to react effectively with its environment. …