This study aims to formulate Animal-Assisted Education guidelines. It was hypothesized that children would experience mental growth through formulating a relationship with a rabbit. We examined the process of mental growth and the ways in which teachers should assist pupils’ development. The method of this study involved conducting participatory fieldwork and recording the behavior of children who were interacting with an elderly rabbit (performing certain duties, communicating with the rabbit, and so on). The results of the research regarding teachers’ involvement in this process revealed five key points: (1) teachers should talk to children about the breeding of animals, (2) teachers serve as role models for children, (3) teachers characterize worth a child’s thoughts, (4) teachers should carefully comprehend what the children think, and 5) teachers should help with the process of shaping children’s behavior. The results of the research into environment configuration for young children raised two important points: (1) Children can become interested in an elderly rabbit and (2) children’s thoughts enable one to face their own thoughts.