An eye-tracking apparatus includes a first lens group, a light splitting device, a display, an image sensor, a second lens group, and a plurality of light sources. The light splitting device receives a first beam, generates a second beam, and transmits the second beam to a second surface of the first lens group. The display projects a reference mark to a target area through the light splitting device and the first lens group. The image sensor captures a detection image on the target area through the first lens group, the light splitting device, and the second lens group. The second lens group is disposed between the light splitting device and the image sensor. The light sources are disposed around the image sensor and project a plurality of beams to the target area through the first lens group, the light splitting device, and the second lens group.