Toward infants whose attachment to their first attachment figures (mainly their mothers) is insecure, how can we intervene in them? To reveal it, an observation was carried out regularly once a week, over a period of 9 months. The subjects were an infant who has insecure attachment and comparative one who has secure attachment. And the attachment behaviors they exhibited toward nursery school teachers, strangers, and an observer were counted. The amount of the attachment behaviors of the infant whose attachment was insecure had been large for 9 months. In conclusion, the infant became to be attached to a nursery school teacher for his first attachment figure, and the infant-teacher attachment began to be secure.