The purpose of this study was to design an elementary school learning environment with a high level of freedom and to verify the changes in self-regulation and academic abilities in children through putting self-determined learning into practice. During a six-month learning period with a mathematics text as the main textbook, an environment in which students could decide for themselves where and how they would study as well as who they would interact with was put in place. The results suggest that the level of autonomous motivation improved. From these results, we can consider that the learning design in this study had the effect of promoting children’s self-regulation abilities. Furthermore, a comparison of test scores from before and after the learning practice suggested that this learning design improves academic results further than conventional teaching methods.