We describe experiments designed to measure gaze direction perception capability of humans under face-to-face and display mediated conditions. Gaze perception capability was determined by means of the absolute values of the pitch differences between a looker's actual regards and participants' judgments. We compared the capability under face-to-face, stereoscopic image, and monoscopic image conditions. On average, participants perceived the looker's gaze direction most accurately under the face-to-face condition. As expected, the accuracy under the stereoscopic image condition was higher than the results obtained under the monoscopic image condition. However, individual data did not follow the expected order and our exploratory experiments showed that participants with narrower interpupillary distance than the distance between two stereo cameras had difficulty in judging gaze directions. We also found that the perception of the pitch component of gaze direction is affected by gaze transmission methods but the yaw component is robust and is not affected by the transmission conditions.