A portable display device capable of preventing the ambient temperature of a light source provided in a liquid crystal display device from being intensively raised. The portable display device is constructed with a liquid crystal display panel; a backlight assembly including light source for supplying light to the liquid crystal display panel, and a mold frame receiving the liquid crystal display panel and the light source as well as surrounding at least two sides of the light source. At least one region of the mold frame surrounding the sides of the light source is formed of at least one aperture.