The visible-spectrum gaze tracker (VSGT), which is designed without the extra Infra-ray (IR) illuminations, has provided a more superior user experience than the traditional IR-based on gaze tracker. However, the head motion compensation for a VSGT appears to be challenging due to the lack of stable glints on the human eyes. In this paper, a new head motion compensation mechanism for binocular VSGT has been proposed. The improvement comes from the fact that the proposed approach can accurately estimate the relative positions/poses among the camera, the screen, and the human eyes. The experimental results show that the proposed approach has led to a promising result of the head motion compensation.