An image display device which includes a parallax adjustment unit, a display unit, a parallax detector, and a maximum parallax detector. The parallax adjustment unit is configured to obtain a right-eye image signal and a left-eye image signal. The parallax adjustment unit is configured to adjust a parallax between the right-eye image signal and left-eye image signal and output an adjusted image signal that includes an adjusted left-eye and adjusted right-eye signal. The parallax detector is configured to detect an amount of parallax between the right-eye and left-eye image signals. The maximum parallax detector is configured to detect a maximum value. The display unit is configured to display a right-eye image and a left-eye image and to display an augmented image including the right-eye image and the left-eye image as well as a monitor image indicating the amount of parallax detected and the maximum value.