The purpose of this study is to examine factors influencing adult learners' lifelong education satisfaction in terms of individual background, institutional characteristics linked to lifelong education policy structure, adult learners' learning experience within the university, thereby deriving implications for improvement quality of university lifelong education. To that end, we surveyed adult learners participating in the ‘Lifelong education at universities for the Future of Education(LiFE)’ project on learning experience and educational satisfaction, and the data of 2,359 students were used for analysis. Utilizing hierarchical multiple regression analysis, this study reveals the following results: First, although there are differences in the detailed areas of satisfaction, individual backgrounds, such as gender, age, major, and status of employment, and institutional characteristics linked to lifelong education projects showed a significant impact on adult learners' lifelong education satisfaction in university life. Second, adult learners' learning experience had a greater influence on lifelong education satisfaction than their individual background and institutional characteristics. Among the learning experiences, thinking ability promotion activities during class and the relative influence of and interaction with the university members were found to be high in particular. Based on the results of this study, the implications for improving the quality of lifelong education were suggested.