This study aimed to explore adolescents’ sense of purpose, including its content, development, affecting factors, and differences among the various contents of their experiences. The participants were 152 junior high school students, 62 boys and 90 girls, between the ages of 13 and 16 (M = 14.16, SD = 0.97). The study designed a structured interview guide for adolescents’ sense of purpose and conducted a 40-mintute interview with each participant. Qualitative content analysis was conducted to analyze verbatim transcription of interview data and induced four contents and relevant experiences of their sense of purpose. The contents of sense of purpose were ambitions for future, life focuses, an ideal life, and an ideal society. The relevant experience was related to contents, reasons, the timing to establish the sense of purpose, engaging and involving, and support from interpersonal sources. We calculated the frequencies of relevant categories and explored the variances between these categories. The results showed that 50% of participants had developed concrete ambitions. Ambitions for future were selected based on participants’ interest and personality characteristics or specialties, external expectations, suggestions or conditions, altruism, and life meaning. Life focuses were related to furthering academic pursuits, parents and family, classmates and friend, interests, and recreations. An ideal life was related to an ideal career, a decent life, a safe and ordinary life, and having a family to live with their parents. An ideal society was perceived as a positive and harmonious society including environmental and ecological conservation, educational and cultural development, and multidimensional justice. There was a significant difference between the age and the time to establish a sense of purpose as well as actions taken. A discussion was provided with suggestions.