As computer science becomes a regular part of the high school curriculum, the need to assess the students’ learning motivation has become crucial. This goes hand in hand with the need to create instructional materials that enhance not only learning performance but motivation as well. An online algorithm learning tool was created to address these needs and was implemented among the students of Tokyo Tech High School of Science and Technology. Two questionnaires on motivation were designed and implemented: the Questionnaire on Motivation, Self-Efficacy and Learning Attitudes (QMSLA), based on Motivated Strategies for Learning Questionnaire (MSLQ) and the Questionnaire on Motivation based on the ARCS model. Using these questionnaires, it has been found that the learning tool contributed to the increase in the motivation of the student participants. Results were then used to propose a revised questionnaire on motivation which was also validated in a subsequent implementation of the learning tool.