We present a gaze estimation method for a head-mounted full-view egocentric camera that can capture egocentric video together with users’ gaze cues. While the conventional gaze recording device has two cameras, an eye camera and a scene camera, the proposed gaze recording device has only a single spherical camera with a full field of view. To determine the point of gaze on full-view images, we present an eye-model-based gaze estimation method by means of three-dimensional iris projection. First, an eye model is built according to the precalibration process of an eyeball center and the eyeball biological parameters; then, we express the 3D iris contour in the eye model and project it back to the spherical camera model. Since 2D iris contours can be detected directly on images and can also be expressed under the spherical model, the relationship between the 3D iris contour and the 2D iris contour can be found. By solving this problem, the gaze direction under the camera model is determined; subsequently, the point of gaze on the images can be inferred. Since in the proposed method, a single spherical camera can play the role of the conventional two cameras, not only do the proposed method results have a simpler system structure but also the cumbersome operation of the calibration for the conventional two-camera gaze measurement devices becomes unnecessary. The effectiveness of the proposed method is shown by the experimental results.