This paper proposes a system that models the interaction in Applied Behavior Analysis(ABA). ABA is a education for Autism children to acquire the ability of communication, and is a kind of reinforcement learning. In the education, when an autism child looks at caregiver's face, then he/she can get a reward from the caregiver. By modeling the interaction and implementing the model to a robot, robot acuires the ability of looking at human face without initial knowledge about face.