Abstract: A warning light device includes a base for receiving a warning light member and having a pair of panels laterally extended outward. A pair of hooks are secured to one of the panels for hooking the base to the back support of the bicycle. Two securing members may engage with the dust shield of the bicycle and two bolts may secure the securing members to the panel so as to secure the base to the bicycle. The base includes a magnet member secured in the bottom portion for attaching the warning light device to the upper portion of the vehicle.