This study is for the implication of editorial design in science textbooks which are designed for student-centered instruction, when the elements of the editorial design are different, we focus on how the students' eye movement and cognitive load change. For this, we produced a new book for 5th grade students in elementary school that is modified by the elements of the editorial design about the visual materials and the alignment of the official textbook. Then we analyzed the eye movement and the cognitive load with an eye-tracker. As a result, first, when the alignment of the body of the textbook was different, there was no significant difference whether it was justified fully or aligned left. Second, the back-up information about the visual materials in the textbook helped students have longer attention span and understand the learning content more.