This study developed a tool for measuring adverse health effects in students who use digital textbooks. The study tool was aimed at 690 sixth-graders who had used digital textbooks for more than a year in schools taking part in the nationwide digital textbook pilot program. We determined the validity and reliability of the tool. The tool for measuring adverse health effects of digital textbooks consisted of a total of 22 items, including 13 on physical symptoms and 10 on psychological symptoms. For the physical symptoms, two factors – whole body/musculoskeletal symptoms and eye symptoms – were extracted. For the psychological symptoms, the two assessed factors included negative and positive psychological symptoms. This tool will not only be helpful in preventing and managing adverse health effects of digital textbook use by identifying various physical and psychological symptoms, but will also be useful as a basis for the expansion of digital textbooks.