The purpose of this study was to identify the effects of social support and self-directed learning ability on the maturity of career attitude of middle school students. For this purpose, 302 middle school students were selected and surveyed. Social support test (Cho, 2010), self-directed learning ability test (Yang, Lee, & Kim, 2018) and career attitude maturity test (Limon et al., 2012) were used in this study for measuring the variables. The results of the study were as follows: First, it confirmed that social support affected career attitude maturity (planning, independence, occupation attitude, self-understanding, information search, rational decision making). Thus, it is required to have accurate recognition of social support to improve career attitude maturity of the middle school students. Second, it confirmed that self-directed learning ability affected middle school students' career attitude maturity. It is necessary to make a special program for proper recognition of self-directed learning ability and its significance to one’s job, and to develop the ability to be self-directed learners at home. Third, there were correlations between social supports, self-directed learning ability, and career attitude maturity. Based on the results of this study, the program is necessary to develop mature attitude towards a career through considering the level of middle school students and confirming the individual’s self-directed learning ability and social support.