An HMD includes: a display which displays a three-dimensional video image; a position obtaining unit which measures a position of an inner corner or tail of an eye of a viewer with respect to the display; a standard position storage unit which obtains and stores, as a standard position relating to the position, the measured position of the inner corner or outer corner of the eye, in calibration for determining the standard position; a position gap detecting unit which detects, as a position gap, a difference between the standard position and a newly measured position of the inner corner or outer corner of the eye of the viewer viewing content with respect to the display; and an image processing unit which performs image processing on the 3D video image to be displayed on the display, to rotated or parallely move the 3D video image according to the detected position gap.