The purpose of this study was to identify what causes dropout for cross-fit hobbyist, one of high-intensity exercises that has recently in the spotlight. Seven cross-fit box users living in metropolitan city A were selected as research participants. In-depth interviews were conducted by mixing unstructured and semi-structured interviews. As findings of the analysis, personal and external factors were emerged as the main theme. Sub-themes of personal factors included maladjustment to high-intensity exercise, injury, burden due to the burden of team members' excessive expectations, and psychological atrophy due to record competition. Sub-themes of external factors included economic burden and conflict with coaches. Based on the findings, the following three suggestions were conducted. First, regular seminars for cross-fit coaches are held. Efforts should be made to strengthen the capabilities of coaches by holding regular seminars with various topics such as injuries and injury prevention that occur when performing cross-fit, effective warm-ups and cool-downs, and coaching theories as well. Second, it is necessary to provide an athletic environment to prevent injury. Additionally, it is important to create an athletic culture and environment to prevent injuries in advance. The third relates to the need for programming for beginners. Excluding record competition for beginners and programs of appropriate difficulty could prevent members from dropout