The purpose of this study is to reveal students’ information gathering behaviors and processes and teacher's approaches to improve their learning outcomes in middle school inquiry-based learning. We compare the dif erences in behaviors in information gathering process between learners with high and low understanding of the themes as their learning outcomes and teachers' approaches for both types of learners.Participants were seventeen ninth grade students and two teachers as their supervisors. During the Period for Integrated Studies, the students searched for information, reflected on their behaviors, and summarized the information they gathered on slides. The analysis targeted seven students who selected themes related to SDG 4 (four students) and SDG 8 (three students) and two teachers. As a result of the analysis, students with a high level of understanding of the themes showed behaviors of browsing and referring to materials corresponding to pillars of investigation (sub-subjects). For the behavior, teachers provided students with supplementary guidance on keyword searches and introductions to websites.