A pattern displaying device includes a light path changing element, a first light source, a second light source, and a control module. The light path changing element has first inclined surfaces to reflect light and arranged into a first predetermined pattern, and second inclined surfaces to reflect light and arranged into a second predetermined pattern. The first light source is operable to emit light toward the first inclined surfaces to display the first predetermined pattern. The second light source is operable to emit light toward the second inclined surfaces in order to display the second predetermined pattern. The control module is electrically connected to the first and second light sources to control the first and second light source to emit light or not.