Provided is a method to easily detect eye motions in the eye moving direction, which has resistance to a fluctuation in background light and to a displacement of the position of a camera. The method includes the steps of: detecting a white area of the eye from the eye area; determining a blood vessel image to be used for a template blood vessel image in the white area of the eye; detecting a nth blood vessel image, which matches the template blood vessel image; calculating a nth moving amount of the eye based on a difference between the reference position and the detection position of the nth blood vessel image, which matches the template blood vessel image; and calculating a nth rotation angle of the eye to detect eye motions in the information processing apparatus.