A computer-readable recording medium storing a displacement determination program is disclosed. First and second face areas of a person are extracted, respectively, from first and second images captured by first and second imaging devices arranged at certain positions where first and second available ranges for detecting a gaze are overlapped. First and second feature points are detected based on light reflections in the first face area and the second face area being extracted. First and second gaze positions of the person are calculated based on the first and second feature points being detected. An arrangement displacement is determined from both or one of the certain positions of the first and second imaging devices based on a relative position relationship between the first and second gaze positions.