Recent gaze tracking research have illustrated patterns of teachers’ visual attention in the classroom. However, the reciprocity of teacher-student interaction needs to be explored using multiple mobile gaze tracking. This descriptive case study is our first step to chart the role of dyadic eye contacts in the teacher-student interaction during collaborative mathematical problem solving. Our results indicate that, during mathematical problem solving, teacher gaze at student faces and student gaze at teacher face vary between whole-class instruction and small-group scaffolding moments. As a conclusion, we suggest that forming dyadic eye contact requires optimal interactional, personal, and environmental states, and this method can offer us fruitful information on the micro-level processes of teacher-student interaction.