A three-dimensional image display device is provided with a display panel. The display panel is provided with a plurality of pixels for the right eyes and pixels for the left eye, and light emitted from the pixels for the right eye is made incident to the right eye of a viewer and light emitted from the pixels for the left eye is made incident to the left eye. When the normal distance between the display panel and the viewer is set to a maximum observation distance, D (mm), then definition X (dpi) of at least one of a vertical direction and a horizontal direction on a display plane of the display panel is set as in the following expression. X ≥ 25.4 D × tan ⁡ ( 1 ′ )