In this study, we investigated how specifically the clients conceptualize the characteristics of a mature person. To do so, we surveyed 61 professional counselors using an open questionnaire and requested them to report the characteristics of mature and immature person as well as, characteristic changes observed after counseling. This collective data were analyzed by applying Censensual Qualitative Research (CQR: Censensual Qualitative Research) method. The features that mature person possess were then classified based on the VIA(Values ​​in Action)(Peterson & Seligman, 2004) system. Our findings revealed the following results. Firstly, the strengths of mature person include kindness, open-mindedness, self-regulation, authenticity, bravery, and social intelligence with unusually high frequency. Secondly, we frequently observed authenticity and social intelligence as the qualities of the clients whose maturity was developed by counseling. Self-regulation, persistence, and kindness were followed. Lastly, we found that immature person tend to show high egocentrism, selfish attitudes, emotional instability, difficulties in interpersonal relationship (lack of social skills, isolation), rigid thinking, hostility, and lack of responsibility.