According to the present disclosure, there is disclosed a method and device for displaying a 3-dimensional image, which may provide an improved depth perception. The method according to present invention comprises: forming parallax images for left eye and right eye, each of the parallax images including a plurality of images corresponding to images at different depths for a same object; controlling a brightness of the images of each of the parallax images for the left eye and the right eye; and displaying the parallax images for the left eye and the right eye.