The purpose of this study is to derive various clues for the establishment of marketing strategies for companies that produce and sell high-involvement products for Millennials who are not the subject of current consumption but who will lead future consumption. For this purpose, this study aimed to derive 17 factors of high-involvement product selection attributes through FGI, and its relationship on repurchase intention after make a variable through PCA. A total of 158 valid questionnaires were used, and IPA, independent sample t-test, regression analysis, and hierarchical controlled regression analysis were performed. The results showed that overall, external and internal selection factors had a positive influence on repurchase intentions, and in particular, appealing to internal and external selection factors in order to promote repurchase intention. Meanwhile, the Millennials were found to have no gender difference. Therefore, the company producing and selling high-involvement products suggests that it is necessary to make a priority effort to secure brand awareness, trust in product producers, store trust, and product self-reputation as components of internal selection factors. It was also concluded that more strategic efforts were needed to focus on and appeal to the characteristics of the Millennial itself rather than to consider gender differences.