— In this paper, a non-intrusive eye gaze estimation system is proposed. The proposed system consists of five light sources and two cameras, and the direction of the user’s eye gaze can be computed by using a projective property without computing the geometrical relation among the eye, the cameras, and the monitor in 3D space. Our method is accurate under head movement, and is comparatively simple and fast. We will introduce our method and show experimental results. The experimental results will verify the feasibility of the proposed system as a human-machine interface.