The purpose of this study was to analyze and compare mind wandering that occurs during the pre-learning and follow-up learning processes using an eye-tracker. For this purpose, 18 students from K University located in the central region of Korea were randomly sampled and selected as the study subjects. First, in the process of learning ‘Earth and Moon’s motion’, pre-service teachers had more Mind Wandering sections in the follow-up learning process, ‘Change in the phase of the moon’, than the ‘Earth rotation and revolution’, which was a prerequisite learning process. Second, it was confirmed that the mind wandering of pre-service teachers appeared faster in the follow-up learning process than in the prelearning process. Third, the total Mind Wandering time in the follow-up learning process was longer than in the pre-learning process, similar to the previous two results, in the total mind wandering time in the pre-learning and follow-up learning process of pre-service teachers. Through this study, it was found that pre-service teachers’ attention was higher in pre-learning than in follow-up learning. In addition, it was found that there is a need for a teacher’s intentional teaching strategy to increase the learner’s attention and reduce mind wandering in follow-up learning.