Many medical students seem to be more interested in clinical medicine topics than in social medicine topics. Through a problem-based, small-group learning course, we examined whether students' degrees of interest differ between topics and change during learning. At the start of the course, students were more interested in clinical/practical medicine topics than in industrial/environmental health topics. However, after the course their degrees of interest in both types of topic had increased and showed no significant difference. In particular, the degree of interest in sociomedical topics increased. In problem-based learning, knowing students' interests in learning about topics helps improve teaching strategies.