When a predetermined image is displayed for a user such that the user is able to visually recognize the image, the user sight line direction is detected, a part assumed to be present in the detected user sight line direction is set to a first image, an image complementary to the first image for the predetermined image is set to a second image, the positions of the retinas of the eyes of the user are scanned with laser light from a retinal scanning display unit fitted to the head of the user and the first image is focused on a position away from the position of the eyes of the user by a first distance and is displayed. The second image is displayed on the surface of the panel of a panel display unit in a position away from the user by a second distance shorter than the first.