Abstract: A pattern-display signal device installed in a motor vehicle for synchronous operation with one directional light is disclosed to include a flat base having a receiving space provided with a reflector, a light transmitting substrate pressed on the reflector in the base, LEDs mounted in the base and aimed at one side of the substrate for synchronous operation with the directional light, a pattern film having a design therein and bonded to the substrate, a lens covered on the pattern film, a first adhesive adhering the lens to the base, and a second adhesive adhering the lens to the motor vehicle.