The purpose of this study was to explore how primary school students develop their interest in science. A survey questionnaire was used to investigate students' interest, change of their interest, and engagement in science related activities three times a year. 201 students of two primary schools in Seoul Metropolitan City initially participated in this study. A follow-up case study was conducted with students who showed an increased interest in science. Finally, seven students were chosen in the case study. They were asked to keep a photo journal for 12 weeks, and were interviewed in every other week by one of the researchers. Among these seven participants, two (TK and QQ) were chosen for analyzing their data in this case study because they showed positive changes in developing science interest throughout the study. The results of two participants' survey, photo-journal and interview were analyzed qualitatively. First, TK, whose science interest developed from situational interest II to individual interest I, engaged in doing experiments at home, doing mathematics activities, raising pets or plants, observing phenomena, and visiting informal educational centers. He tended to participate in hands-on activities by himself in out-of-school settings. Second, QQ who developed from situational interest I to situational interest II, engaged in taking pictures as a representative activity at home and school. He tended to participate in activities with either his father or one of the researchers. Both students showed personal characteristics such as doing place-based activities, interaction with others and activity subjectivity. The goal of TK's interactions with others on the various places was to develop in cognitive domain. On the contrary, QQ's goal of interactions with others was to develop in emotional communication. This study reported the cases of characteristics of students who developed their interests in science including activities in-and out-of-school settings and their accompanying people.Keywords: interest in science, development of interest in science, science activity, photo-journal 요 약: 이 연구의 목적은 과학 흥미가 발달한 초등학생의 특성을 심층적으로 탐색하는 것이다. 서울 소재 2개의 초등학 교 201명을 대상으로 1년 동안 3차례에 걸쳐서 흥미 변화, 과학과 관련된 활동의 선호도와 참여도에 대한 설문조사를 실시하였다. 3차례의 설문조사에서 과학 흥미에 유의미한 변화를 보인 학생들을 대상으로 사례연구 참여 대상자를 모집 하였다. 사례연구 참여에 동의한 7명의 학생들에게 12주에 걸쳐서 매일 과학관련 활동 포토저널을 작성해 줄 것을 요 구하였다. 또한 연구 참여자는 2주에 한 번씩 연구자 중 한 명을 만나 총 6차례 반-구조화된 인터뷰에 참여하였다. 7명 의 사례연구 참여자 중에서 과학 흥미가 상황적 흥미 II 수준까지 발달한 학생 1인과 개인적 흥미 I 수준까지 발달한 학생 1인, 총 2명(TK와 QQ)을 대표 사례로 선정하여 심층 분석을 실시하였다. 분석대상 자료는 설문조사 결과와 포토 저널과 면담내용이었다. TK 학생은 상황적 흥미 II 수준에서 개인적 흥미 I 수준까지 발달한 사례로서 주로 집에서 직