Passion is defined as a strong inclination toward an activity that one likes, that one finds important, and in which one invests time and energy. These activities are eventually internalized as part of one’s identity. The Dualistic Model of Passion posits the existence of two types of passion - harmonious and obsessive passion (Vallerand et al., 2003; Vallerand, 2015). These two types of passion have been assessed through the Passion Scale (Marsh et al., 2013). The purpose of the present study was to develop a Japanese version of the Passion Scale and to evaluate its reliability and validity. In Study 1, Japanese university students completed a questionnaire that examined the relationship between the Passion Scale and measures of flow, concentration, anxiety, shame, depression, wellbeing and positive and negative affect. In Study 2, we examined the test-retest reliability. The results provided support for the two-factor structure of the Japanese Passion Scale and showed high reliability and validity. Overall, this evidence supports the practical applicability of the Japanese Passion Scale.