Experiments on animals has been playing very important part in psychology, medical science, genetics and brain science. Rodents are one of the most popular experimental subjects in these experiments. In psychology and brain science, behavior test and analysis on rodents, especially rats, has been performed to clarify mechanisms of mind or brain functions. "Open-field test" is one of the most popular research methods to investigate their behavior. In the "open-field test," rats are released into the "open-field," circle or square, flat arena surrounded by walls, and their behavior parameters such as position, moving distance, number of grooming and rearing are measured. With conventional experimental setups, these parameters has been measured and recorded by humans. Observing and recording are heavy task for experimenters, and also involves some human errors and subjectivity. Therefore, we developed an autonomous experimental setup which measures rats' position, number of grooming and rearing in the open-field. In addition, an active tracking camera which takes high resolution images of the rat in the open-field was developed. To prevent losing tracks of the rat, a prediction model of rat's movement is developed and integrated into the control of this camera.