In this study, we aim to create systematic contents that pupils can acquire the depth cognition on space. So in this paper, we made a piece of contents ("Notice changes of a plane") for 3rd graders. and we investigated development of their depth cognition through an educational experiment. The result of our experiment shows the next points. About 90% pupils'cognition was developed, and then about 40% pupils acquired the depth cognition. Namely, 3rd graders'depth cognition on space was developed by the contents.